We are given the following information about a function f : f′(x)=x+12,f(0)=1. We want to use this information to estim
Posted: Thu Jul 14, 2022 4:46 pm
We are given the following information about a function f : f′(x)=x+12,f(0)=1. We want to use this information to estimate f(3). In Problem 1, we will use a linear approximation. In Problem 2, we will break up the interval [0,3] into smaller parts to come up with a better approximation. This process is called Euler's Method. In Problem 3, we will find an exact values for f(3) and see which approximation was better. And in Problem 4 we will graph all of the relevant functions to see what is going on.
The problem with this approximation is that x=3 is relatively far from x=0. Over the interval [0,3], the function f(x) bends away from the linear approximation function L0(x). We can get a better estimate by using a technique called Euler's Method. In this method, we will define a piecewise function E(x)=⎩⎨⎧m0x+b0m1x+b1m2x+b2 if 0≤x≤1 if 1<x≤2 if 2<x≤3 Note that the function has 3 different pieces, and each piece is a straight line. We will want this function to satisfy the following properties: - E(x) is continuous on the interval [0,3]. In particular, this includes the splitting points x=1 and x=2, and - The slope of the line over the interval (n,n+1) should be f′(n). This requirement means that the derivative f′(x) will be used to direct E(x). Once we have constructed E(x), we can use it to estimate f(3)≈E(3). To construct E(x), we need to find appropriate values for the constants m0,m1,m2,b0,b1,b2. Complete the following steps to find these values. (a) The constants m0,m1,m2 are the slopes of the three different pieces of E(x). The slope over the interval (n,n+1) should be f′(n). Use this relation for n=0,n=1, and n=2 to find the values for m0,m1, and m2. (b) The constant b0 should be chosen so that E(0)=f(0). Use the given value of f(0) to find the correct value for b0.
(c) We have now found values for b0,m0, and m1. Use these to find a value for b1 which makes E(x) continuous at x=1. Make sure you use the definition of continuity. (d) We have now found values for b1,m1, and m2. Use these to find a value for b2 which makes E(x) continuous at x=2. Make sure you use the definition of continuity. (e) We've now found all of the necessary constants. Summarize your findings by filling in the following for E(x) : E(x)=⎩⎨⎧ if 0≤x≤1 if 1<x≤2 if 2<x≤3 (f) Use the function E(x) to approximate f(3). [ Hint: f(3)≈E(3).]
The problem with this approximation is that x=3 is relatively far from x=0. Over the interval [0,3], the function f(x) bends away from the linear approximation function L0(x). We can get a better estimate by using a technique called Euler's Method. In this method, we will define a piecewise function E(x)=⎩⎨⎧m0x+b0m1x+b1m2x+b2 if 0≤x≤1 if 1<x≤2 if 2<x≤3 Note that the function has 3 different pieces, and each piece is a straight line. We will want this function to satisfy the following properties: - E(x) is continuous on the interval [0,3]. In particular, this includes the splitting points x=1 and x=2, and - The slope of the line over the interval (n,n+1) should be f′(n). This requirement means that the derivative f′(x) will be used to direct E(x). Once we have constructed E(x), we can use it to estimate f(3)≈E(3). To construct E(x), we need to find appropriate values for the constants m0,m1,m2,b0,b1,b2. Complete the following steps to find these values. (a) The constants m0,m1,m2 are the slopes of the three different pieces of E(x). The slope over the interval (n,n+1) should be f′(n). Use this relation for n=0,n=1, and n=2 to find the values for m0,m1, and m2. (b) The constant b0 should be chosen so that E(0)=f(0). Use the given value of f(0) to find the correct value for b0.
(c) We have now found values for b0,m0, and m1. Use these to find a value for b1 which makes E(x) continuous at x=1. Make sure you use the definition of continuity. (d) We have now found values for b1,m1, and m2. Use these to find a value for b2 which makes E(x) continuous at x=2. Make sure you use the definition of continuity. (e) We've now found all of the necessary constants. Summarize your findings by filling in the following for E(x) : E(x)=⎩⎨⎧ if 0≤x≤1 if 1<x≤2 if 2<x≤3 (f) Use the function E(x) to approximate f(3). [ Hint: f(3)≈E(3).]