Math 104 A Numerical Analysis I Winter 2022 Homework II
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Math 104 A Numerical Analysis I
Winter 2022
Homework II
1. (20 points) 1. Write a computer code to implement the Composite Trapezoidal Rule.
to approximate the definite integral
using the equally spaced points x0 = a, x1 = x0 +h, x2 = x0 +2h, . . . , xN = x0 +Nh = b, where
● Test your code with f (x) = in [0,2] by computing the error |I(f) - Th (f)| for h = , , , and verify that Th (f) has a convergence trend at the expected quadratic rate.
● Let f (x) = ′x in [0,1]. Compute T4(尸) for N = 16, 32, 64, 128. Do you see a second
order convergence to the exact value of the integral? Explain.
2. (50 points) Consider the definite integral I(cos(x2 )) = 0′ cos x2 dx We cannot calcu- late its exact value but we can compute accurate approximations to it using Th (cos x2 ). Let
● Using your code, find a value of h for which q(h) is approximately equal to 4.
● Get an approximation of the error, I(cos x2 ) - Th (cos x2 ), for that particular value
of h.
● Use this error approximation to obtain the extrapolated, improved, approximation
● Explain why Sh (cos x2 ) is more accurate and converges faster to I(cos(x2 )) than Th (cos x2 )
● Let
Using your code, find a value of h for which q1 (h) is approximately equal to 16.
3. (30 points) Show that these assertions are not true.
● ex - 1 = 0(x2 ) as x - 0
● x−2 = 0(cot x) as x - 0
● cot x = o(x− 1 ) as x - 0
2022-01-19