2024 Trapezoidal rule and simpson

This calculus video tutorial on numerical integration provides a basic introduction into the trapezoidal rule which can be used to estimate the value of a de...Here are the steps that explain how to apply Simpson's rule for approximating the integral b ∫ₐ f (x) dx. Step 1: Identify the values of 'a' and 'b' from the interval [a, b], and identify the value of 'n' which is the number of subintervals. Step 2: Use the formula h = (b - a)/n to calculate the width of each subinterval. Another useful integration rule is the Trapezoidal Rule. Under this rule, the area under a curve is evaluated by dividing the total area into little trapezoids rather than rectangles. Let f (x) be continuous on [a, b]. We partition the interval [a, b] into n equal subintervals, each of width. Figure 1. Trapezoidal Rule. ≤ 1. Simpson’s 1/3 Rule. ≤ 2. Simpson’s 3/8 Rule. ≤ 3. From the above table, it is clear that both Trapezoidal Rul e polynomials of degree ≤ 1. Alternate Method. We know, While deriving the formula …📒⏩Comment Below If This Video Helped You 💯Like 👍 & Share With Your Classmates - ALL THE BEST 🔥Do Visit My Second Channel - https://bit.ly/3rMGcSAThis vi...Ragab Khalil. SUMMARY The trapezoidal rule and Simpson’s rule are numerical approximation methods to be used to approximate the area under a curve. The area is divided into (n) equal pieces, called a subinterval or trapezoid. Each subinterval is approximated as a trapezoid considering the outer edge as straight line in the trapezoidal rule. For the Trapezoidal Rule, you actually use $n+1$ points. For example, in the simple case where you are integrating $f(x)$ from $0$ to $1$, and you want $T_4$, you ...Solution. a. Given the value of n = 10 of the irregularly shaped figure, identify the height values from y 0 to y 10. Create a table and list all the height values from left to right for a more organized solution. Calculating the Approximate Area of Irregular Shapes Using Simpson’s 1/3 Rule. Variable (y) Height Value.AP Calculus. About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday TicketFor the Trapezoidal Rule, you actually use $n+1$ points. For example, in the simple case where you are integrating $f(x)$ from $0$ to $1$, and you want $T_4$, you ...May 31, 2022 · We now use our elementary formulas obtained for (6.2) to perform the integral given by (6.1) ( 6.1) 6.2.1. Trapezoidal rule. We suppose that the function f(x) f ( x) is known at the n + 1 n + 1 points labeled as x0,x1, …,xn x 0, x 1, …, x n, with the endpoints given by x0 = a x 0 = a and xn = b x n = b. Define. Use the Trapezoidal Rule, the Midpoint Rule, and Simpson's Rule to approximate the given integral with the specified value of n. (Round your answers to six decimal places.) •π/2 1 + cos (x) dx, (a) the Trapezoidal Rule 4.461538 X (b) the Midpoint Rule (c) Simpson's Rule Submit Answer n = 4. Try focusing on one step at a time. You got this!36 Comparison on Trapezoidal and Simpson’s Rule for Unequal Data Space 3.3 Simpsons 3/8 Rule Putting n 3in Eqn. (2) then we got for the interval [,]x03x 3 0 2 30 23 3 030 01 012 3031 31 01 23 ...1 Answer. Sorted by: 1. Simpson's rule is exact for polynomials upto degree 3, so it is preferable compared to the trapezoidal rule (only exact for polynomials upto degree 1). In the concrete. situation, you have 8 nodes, so that you cannot use simpson's rule alone. Trapezoidal Approximation = LRAM + RRAM 2 . Note: the previous 4 methods are also called Riemann Sums after the mathematician Bernhard Riemann. Simpson's Rule. An improvement on the Trapezoidal Rule is Simpson's Rule. It is based on using parabolas at the top instead of straight lines. The parabolas often get quite close to the real curve:Question: Use the trapezoidal rule, the midpoint rule, and Simpson's rule to approximate the given integral with the specified value of n. (Round your answers to six decimal places.) ∫0239−x2dx,n=10 (a) the trapezoidal rule (b) the midpoint rule (c) Simpson's rule. Show transcribed image text. There are 2 steps to solve this one.Introduction. Simpson’s Rule is a numerical method used in calculus to estimate definite integrals. While it’s a powerful technique, it’s essential to assess the accuracy of the results it provides.In Simpson’s 1/3 Rule, we use parabolas to approximate each part of the curve.We divide. the area into n equal segments of width Δx. Simpson’s rule can be derived by approximating the integrand f (x) (in blue) by the quadratic interpolant P (x) (in red). In order to integrate any function f (x) in the interval (a, b), follow the steps ...6.2: Composite Rules. We now use our elementary formulas obtained for (6.2) to perform the integral given by (6.1) ( 6.1) 6.2.1. Trapezoidal rule. We suppose that the function f(x) f ( x) is known at the n + 1 n + 1 points labeled as x0,x1, …,xn x 0, x 1, …, x n, with the endpoints given by x0 = a x 0 = a and xn = b x n = b. Define.The trapezoid rule with n = 6 partitions. The “error” is the difference between the actual “true” value and the approximation. Errors in the trapezoidal rule and Simpson’s rule can be calculated with a couple of straightforward formulas; These are useful when we want to increase the accuracy of an approximation.called the Trapezoidal rule and the Simpson’s rule which can be derived by integrating the Lagrange interpolating polynomials of degree 1 and 2 respectively. In the second type we shall consider some good formulas. The use of the closed Newton-Cotes and other integration formulas of order higher than the Simpson’s# Write a program to evaluate a definite integral using Simpson's rule with # n subdivisions from math import * from pylab import * def simpson(f, a, b, n ... Simpson's should be more accurate than the trapezoidal rule. I also wrote a program for the trapezoidal rule. With n=100, the trapezoidal rule gives me the exact answer (0.5 ...Simpson's rule is a method of numerical integration which is a good deal more accurate than the Trapezoidal rule and should always be used before you try anything fancier. It also divides the area under the function to be integrated, f ( x ) , into vertical strips but instead of joining the points f ( x i ) with straight lines, every set of three such successive points is …Free Simpson's Rule calculator - approximate the area of a curve using Simpson's rule step-by-stepSimpson's rules in the case of narrow peaks. In the task of estimation of full area of narrow peak-like functions, Simpson's rules are much less efficient than trapezoidal rule. …Simpson’s 1/3 Rule. Simpson’s 1/3rd rule is an extension of the trapezoidal rule in which the integrand is approximated by a second-order polynomial. Simpson rule can be derived from the various way using Newton’s divided difference polynomial, Lagrange polynomial and the method of coefficients. Simpson’s 1/3 rule is defined by: Here the trapezoidal rule approximates the function by a suitably chosen (not necessarily horizontal) line segment. The function values at the two points in the interval are used in the approximation. While Simpson's rule uses a suitably chosen parabolic shape (see Section 4.6 of the text) and uses the function at three points. Use the Trapezoidal Rule, the Midpoint Rule, and Simpson's Rule to approximate the given integral with the specified value 1/2 2 sin (x2) dx, n = 4 Jo (a) the Trapezoidal Rule .128230 X (b) the Midpoint Rule (c) Simpson's Rule n. (Round your answers to six decimal places.) There are 2 steps to solve this one.In the Trapezoid rule method, we start with rectangular area-elements and replace their horizontal-line tops with slanted lines. The area-elements used to approximate, say, the area under the graph of a function and above a closed interval then become trapezoids. Simpson’s method replaces the slanted-line tops with parabolas. The Trapezoidal Quadrature Rule (obtained by first degree Lagrange interpolating polynomial) Let ... Figure 2 Simpson's RuleTrapezoidal and simpson rule question here? The trapezoidal rule applied on ∫2 0 [f(x)]dx ∫ 0 2 [ f ( x)] d x gives the value 5 and the Midpoint rule gives the value 4. What value does Simpson's rule give? So we have that T=f (0)+f (2). f (1) here is equal to 4 since its the midpoint value.. I dont how how to combine these together to find ...Oct 5, 2023 · Introduction. The trapezoidal rule is based on the Newton-Cotes formula that if one approximates the integrand by an nth order polynomial, then the integral of the function is approximated by the integral of that nth order polynomial. Integrating polynomials is simple and is based on the calculus formula. Figure 7.2.1.1. There are different types of numerical approximations; Simpsons rule, Trapezoidal rule, Midpoint rule, Boole’s rule and so on. What is Simpson’s Rule? Simpson’s rule is one of the Newton-Cotes formulas used for approximating the value of a definite integral.The Simpson’s 1 / 3 Rule for Integration. An individual can also get a quicker approximations for definite integrals by dividing a small interval [a,b] into two parts. This means that after dividing the interval, one would get: X0 = a, x1 = a + b, and x2 = b. This means that the approximation can be written as:Nov 16, 2022 · Section 7.10 : Approximating Definite Integrals. In this chapter we’ve spent quite a bit of time on computing the values of integrals. However, not all integrals can be computed. A perfect example is the following definite integral. ∫ 2 0 ex2dx ∫ 0 2 e x 2 d x. Hi everyone!Today I am solving a surveying problem, calculating an area using Trapezoidal and Simpson's Rule. Both formulas are found in the FE Handbook, so ...a) the trapezoidal rule. b) simpson’s rule. solution: here the intervals between the offsets are not reglar through out the length. So, the section is divided into three compartments. Let ∆ I = area of the first section ∆ II = …AP Calculus. About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday TicketWith the trapezoidal rule, we approximated the curve by using piecewise linear functions. What if we were, instead, to approximate a curve using piecewise quadratic functions? …Here the trapezoidal rule approximates the function by a suitably chosen (not necessarily horizontal) line segment. The function values at the two points in the interval are used in the approximation. While Simpson's rule uses a suitably chosen parabolic shape (see Section 4.6 of the text) and uses the function at three points. This calculus video tutorial on numerical integration provides a basic introduction into the trapezoidal rule which can be used to estimate the value of a de...Geometrically, as shown in x8.7 of the text, the trapezoidal approximation and Simpson’s rule use a line and a parabola (polynomials of degree 1 and 2), respectively, to approximate y = f(x) in each Geometrically, as shown in x8.7 of the text, the trapezoidal approximation and Simpson’s rule use a line and a parabola (polynomials of degree 1 and 2), respectively, to approximate y = f(x) in each The variable force to move the abject is F\x) - 100XV 125 - 3. where F is given in pounds and x gives the position of the unit in feet. Use Simpson's Rule with n = 12 to approximate the work w (in foot-pounds) done through one cycle when F (x) dx W -6°F) (Round your answer to two decimal places.) W-10330.27 X ft-lb Need Help?The Trapezoidal Quadrature Rule (obtained by first degree Lagrange interpolating polynomial) Let ... Figure 2 Simpson's Rule$\begingroup$ I'm having trouble understanding the actual process of starting with the trapezoid rule, performing an explicit extrapolation step, and having the result be something resembling Simpson's rule. I understand that they're in the same "family", but what is the direct correlating step that shows this to be the case. $\endgroup$ – NeuraxWolfram|Alpha Widgets: "Trapezoidal Rule Calculator" - Free Mathematics Widget. Trapezoidal Rule Calculator. Added Feb 23, 2017 by potthoff in Mathematics. Gives the approximation of a definite integral using the Trapezoidal Rule. Send feedback | Visit Wolfram|Alpha. Get the free "Trapezoidal Rule Calculator" widget for your website, blog ... $\begingroup$ I'm having trouble understanding the actual process of starting with the trapezoid rule, performing an explicit extrapolation step, and having the result be something resembling Simpson's rule. I understand that they're in the same "family", but what is the direct correlating step that shows this to be the case. $\endgroup$ – NeuraxThe trapezoid rule with n = 6 partitions. The “error” is the difference between the actual “true” value and the approximation. Errors in the trapezoidal rule and Simpson’s rule can be calculated with a couple of straightforward formulas; These are useful when we want to increase the accuracy of an approximation.Considering the Trapezoidal Rule and the Simpson Rule: Which one is more accurate?. For me, it seems to be the Simpson Rule (because it uses quadratic functions compared to linear functions with the trapezoidal rule), but I recently found statements that it isn't true for all cases (but for the most).Boole's Rule, Hardy's Rule, Newton-Cotes Formulas, Simpson's 3/8 Rule, Simpson's Rule, Weddle's Rule Explore with Wolfram|Alpha. More things to try: trapezoidal rule ... , G. "The Trapezoidal and Parabolic Rules." The Calculus of Observations: A Treatise on Numerical Mathematics, 4th ed. New York: Dover, pp. 156 …Question: Use the Trapezoidal Rule, the Midpoint Rule, and Simpson's Rule to approximate the given integral with the specified value of n. (Round your answers to six decimal places.) ∫034+y51dy,n=6 (a) the Trapezoldal Rule (b) the Midooint Rule (c) Simpson's Rule. There are 4 steps to solve this one.Oct 21, 2020 · Considering the Trapezoidal Rule and the Simpson Rule: Which one is more accurate?. For me, it seems to be the Simpson Rule (because it uses quadratic functions compared to linear functions with the trapezoidal rule), but I recently found statements that it isn't true for all cases (but for the most). In this video, I explained how to write MATLAB code for Trapezoidal rule and Simpson's 1/3 rule to evaluate definite integralsWhen you use a greater and greater number of trapezoids and then zoom in on where the trapezoids touch the curve, the tops of the trapezoids get closer and closer to the curve. If you zoom in “infinitely,” the tops of the “infinitely many” trapezoids become the curve and, thus, the sum of their areas gives you the exact area under the ...The answer is yes! Like the Trapezoidal Rule, Simpson's Rule is another numerical integration technique used to approximate an integral that may be too difficult to compute directly. Unlike the Trapezoidal Rule, Simpson's Rule uses quadratic polynomial approximation, making it a more accurate integral estimation technique.In Simpson’s 1/3 Rule, we use parabolas to approximate each part of the curve.We divide. the area into n equal segments of width Δx. Simpson’s rule can be derived by approximating the integrand f (x) (in blue) by the quadratic interpolant P (x) (in red). In order to integrate any function f (x) in the interval (a, b), follow the steps ...Here, we will discuss the trapezoidal rule of approximating integrals of the form = ∫ ( ) b a I. f x. dx. where . f (x) is called the integrand, a = lower limit of integration . b = upper limit of integration . What is the trapezoidal rule? The trapezoidal rule is based on the NewtonCotes formula that if one appro- ximates the integrand by an ...Trapezoidal rule for definite integrals: Enter a function f(x), use the a and b sliders to choose the limits of integration, and use the n slider to increase the number of subintervals. 1 f x = x e − 0 . 5 x This calculus video explains how to perform approximate integration using the trapezoidal rule, the simpson's rule, and the midpoint rule. It covers the err...Simpson’s rule; Right Hand Example; Midpoint Example; See also: Errors in the Trapezoidal Rule and Simpson’s Rule. Riemann Sums Definition. A Riemann sum is a way to approximate the area under a curve using a series of rectangles; These rectangles represent pieces of the curve called subintervals (sometimes called subdivisions or …Simpson’s 1/3 Rule. Simpson’s one-third rule or Simpson’s ⅓ rule is generally considered as an extension of the trapezoidal rule in which a second-order polynomial approximates the integrand. Simpson’s rule can be derived from the various ways using Newton’s divided difference polynomial, Lagrange polynomial, and the coefficients ...Here, we will discuss Simpson’s 1/3 rule of integral approximation, which improves upon the accuracy of the trapezoidal rule. Here, we will discuss the Simpson’s 1/3 rule of approximating integrals of the form. = ∫ f ( x ) dx. where f (x ) is called the integrand, = lower limit of integration. = upper limit of integration.The display then exhibits the Simpson Rule and Trapezoidal Rule approximations for the value of the integral. Note that with this program, the number of subintervals for each rule is even. To execute the program again, just key in ENTER. Identification of italicized words in the program: Input (PRGM > 1) Label (PRGM 9) Goto (PRGM ) IS > ( (PRGM ...The trapezoidal rule can be applied to solve the definite integral of any given function. It calculates the area under the curve formed by the function by dividing it into trapezoids and is a lesser accurate method in comparison to Simpson’s Rule. a common denominator with the Trapezoidal Rule. Simpson’s Rule is a useful formula to know, since it is more efficient than finding Midpoint Rule and Trapezoidal Rule estimates first, then combining the two. Also, the comprehensive formula is more accurate, since rounding errors introduced in the Midpoint and Trapezoidal Rules would get ...Simpson’s 1/3 Rule. Simpson’s 1/3rd rule is an extension of the trapezoidal rule in which the integrand is approximated by a second-order polynomial. Simpson rule can be derived from the various way using Newton’s divided difference polynomial, Lagrange polynomial and the method of coefficients. Simpson’s 1/3 rule is defined by: The Trapezoidal Quadrature Rule (obtained by first degree Lagrange interpolating polynomial) Let ... Figure 2 Simpson's RuleHere the trapezoidal rule approximates the function by a suitably chosen (not necessarily horizontal) line segment. The function values at the two points in the interval are used in the approximation. While Simpson's rule uses a suitably chosen parabolic shape (see Section 4.6 of the text) and uses the function at three points. Next: Simpson's Rule Up: Numerical Integration Previous: A General Quadrature Formula Contents. Trapezoidal Rule Here, the integral is computed on each of the sub-intervals by using linear interpolating formula, i.e. for and then summing them up to …Here the trapezoidal rule approximates the function by a suitably chosen (not necessarily horizontal) line segment. The function values at the two points in the interval are used in the approximation. While Simpson's rule uses a suitably chosen parabolic shape (see Section 4.6 of the text) and uses the function at three points.numpy.trapz. #. numpy.trapz(y, x=None, dx=1.0, axis=-1) [source] #. Integrate along the given axis using the composite trapezoidal rule. If x is provided, the integration happens in sequence along its elements - they are not sorted. Integrate y ( x) along each 1d slice on the given axis, compute ∫ y ( x) d x .Numerical Integration Using Trapezoidal Method C Program. C program for Trapezoidal Rule or Method to find numerical integration. To learn algorithm about Trapezoidal rule follow article Trapezoidal Method Algorithm. #include<stdio.h> #include<conio.h> #include<math.h> /* Define function here */ #define f (x) 1/ (1+pow (x,2)) int main() { float ...Use the Trapezoidal Rule, the Midpoint Rule, and Simpson's Rule to approximate the given integral with the specified value 1/2 2 sin (x2) dx, n = 4 Jo (a) the Trapezoidal Rule .128230 X (b) the Midpoint Rule (c) Simpson's Rule n. (Round your answers to six decimal places.) There are 2 steps to solve this one.The trapezoid rule with n = 6 partitions. The “error” is the difference between the actual “true” value and the approximation. Errors in the trapezoidal rule and Simpson’s rule can be calculated with a couple of straightforward formulas; These are useful when we want to increase the accuracy of an approximation. See Answer. Question: Approximate the definite integral using the Trapezoidal Rule and Simpson's Rule with n = 4. Compare these results with the approximation of the integral using a graphing utility. (Round your answers to four decimal places.) [Th f (x) dx, Trapezoidal 0.271 Simpson's 0.257 graphing utility 0.256 = sin (x) X 1, XXX X>0 X = 0.Therefore, we apply Trapezoidal rule, Simpson’s 1/3 rule and Simpson’s 3/8 rule to solve various numerical problems and compare the result with their exact solution. We have found that Simpson’s 1/3 rule gives better result than …AP Calculus. About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket# Write a program to evaluate a definite integral using Simpson's rule with # n subdivisions from math import * from pylab import * def simpson(f, a, b, n ... Simpson's should be more accurate than the trapezoidal rule. I also wrote a program for the trapezoidal rule. With n=100, the trapezoidal rule gives me the exact answer (0.5 ...Expert-verified. given that the distances in the lake are at intervals of 50 feet. Use the trapezoidal rule and Simpson's rule to approximate the surface area of the lake. Assume each subinterval is 50 feet wide and that the distance across at the endpoints is 0 feet. a.) Trapezoidal rule: 12100 units 2 Simpson's rule: 19200 units 2 b.)

Numeric integration with Trapezoidal and Simpson's rule. I am trying to write a code that allows a user pick between Trapezodal and simpsons method of integration and then after picking the code will let the integrate a given formula 𝑦 = 𝑥 −1 + √𝑥𝑒 ^x . My code is not running however and i was wondering where I may be going wrong.. Jennifer lopezpercent27s nude pictures

Before we start applying Simpson’s rule we must know the proper use of it. That is why we have to solve a couple of problems for having a hands-on grip. Problem # 01: Use simpsons rule with n = 3 to approximate the integral below: $$ \int\limits_0^6 {\sqrt x dx}. $$ Solution: The given integral is: $$ \int\limits_{0}^{6} \sqrt{x}\, dx $$1 Answer. Sorted by: 1. Simpson's rule is exact for polynomials upto degree 3, so it is preferable compared to the trapezoidal rule (only exact for polynomials upto degree 1). In the concrete. situation, you have 8 nodes, so that you cannot use simpson's rule alone. Trapezoidal and simpson rule question here? The trapezoidal rule applied on ∫2 0 [f(x)]dx ∫ 0 2 [ f ( x)] d x gives the value 5 and the Midpoint rule gives the value 4. What value does Simpson's rule give? So we have that T=f (0)+f (2). f (1) here is equal to 4 since its the midpoint value.. I dont how how to combine these together to find ...1 Answer. Sorted by: 1. Simpson's rule is exact for polynomials upto degree 3, so it is preferable compared to the trapezoidal rule (only exact for polynomials upto degree 1). In the concrete. situation, you have 8 nodes, so …The trapezium rule and Simpson's rule are both examples of a family of numerical integration methods called closed Newton-Cotes formulas. The next method in the family is Simpson's 3/8 rule which approximates f f by a cubic function in each interval. Newton-Cotes formulas are especially easy to apply since the function being integrated is ...Q = trapz (Y) computes the approximate integral of Y via the trapezoidal method with unit spacing. The size of Y determines the dimension to integrate along: If Y is a vector, then trapz (Y) is the approximate integral of Y. If Y is a matrix, then trapz (Y) integrates over each column and returns a row vector of integration values. Numeric integration with Trapezoidal and Simpson's rule. I am trying to write a code that allows a user pick between Trapezodal and simpsons method of integration and then after picking the code will let the integrate a given formula 𝑦 = 𝑥 −1 + √𝑥𝑒 ^x . My code is not running however and i was wondering where I may be going wrong.A step-by-step explanation of how to use the trapezoidal rule to find the area of an integral.My health channel: @zamaanwellnessUse the Trapezoidal Rule, the Midpoint Rule, and Simpson's Rule to approximate the given integral with the specified value 1/2 2 sin (x2) dx, n = 4 Jo (a) the Trapezoidal Rule .128230 X (b) the Midpoint Rule (c) Simpson's Rule n. (Round your answers to six decimal places.) There are 2 steps to solve this one.Q = trapz (Y) computes the approximate integral of Y via the trapezoidal method with unit spacing. The size of Y determines the dimension to integrate along: If Y is a vector, then trapz (Y) is the approximate integral of Y. If Y is a matrix, then trapz (Y) integrates over each column and returns a row vector of integration values. In the task of estimation of full area of narrow peak-like functions, Simpson's rules are much less efficient than trapezoidal rule. Namely, composite Simpson's 1/3 rule requires 1.8 times more points to achieve the same accuracy as trapezoidal rule. Composite Simpson's 3/8 rule is even less accurate. Nov 24, 2023 · Step 1: Mark the value of sub-intervals, “n” and intervals “a” and “b”. Step 2: Find the width of sub-interval ( x) using the formula x = (b – a)/n. Step 3: Put all the values in the trapezoidal rule formula and find the approximate area of the given curve which represents the definite integral ∫ba f (x) dx. Trapezoidal rule for definite integrals: Enter a function f(x), use the a and b sliders to choose the limits of integration, and use the n slider to increase the number of subintervals. 1 f x = x e − 0 . 5 x May 31, 2022 · We now use our elementary formulas obtained for (6.2) to perform the integral given by (6.1) ( 6.1) 6.2.1. Trapezoidal rule. We suppose that the function f(x) f ( x) is known at the n + 1 n + 1 points labeled as x0,x1, …,xn x 0, x 1, …, x n, with the endpoints given by x0 = a x 0 = a and xn = b x n = b. Define. .

Oct 5, 2023 · Introduction. The trapezoidal rule is based on the Newton-Cotes formula that if one approximates the integrand by an nth order polynomial, then the integral of the function is approximated by the integral of that nth order polynomial. Integrating polynomials is simple and is based on the calculus formula. Figure 7.2.1.1.

Popular Topics