Math 128A, Spring 2020: Final Exam 2020
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UCB Math 128A, Spring 2020: Final Exam
2020
1. TRUE or FALSE? prove or disprove the following statements (no points for correct answer without a valid proof):
a) (2 points) If f e C1 [a, b] and |f( (① )| 三 1 for all ① e [a, b], then there can be at most one number p e [a, b] for which f (p) = 2p.
b) (2 points) If f (① ) is Lipschitz on (—钝, 钝), then so is f (① )2 on (—钝, 钝).
2. a) (3 points) show that the ixed point iteration
pn = , n = 1, 2, . . .
converges for any initial po e [0, 1].
b) (1 point) Estimate how many iterationsnare required to obtain an absolute error |pn - p| less than 10-4 when po = 1. No numerical value needed, just give an expression for n.
3. (3 points) Find the fourth degree polynomial f (从) which satisies the conditions
f (0) = 1, f (1) = 2, f\ (1) = a, f (2) = 2a, f\ (2) = 2a
4. (4 points) Find the values of c1 , c2 , ①3 , where ①3 e [0, 3], such that the quadrature rule l03 f (① ) d① = c1 f (0) + c2 f (1) + f (①3 ) has the highest possible degree of precision.
5. consider the following MATLAB code:
function w = magic1(N)
h = 1 / N; w = 1; t = θ;
for i = 1:N
w = w - h * (w * t入2);
t = t + h;
end
end
a) (2 points) The function computes a number 山. Describe what this number is approximating in terms of a diferential equation.
b) (2 points) solve this equation analytically to ind the exact value of the number that the code is approximating (Hint: use separation of variables).
C) (3 points) Find an N that would guarantee an error of at most 10 —3 in the ap- proximation.
6. (3 points) consider the n-by-n matrix A With entries
(1 if i = j,
aij = 1 1 if j = n,
' ' if i 持 j,
('0 otherWise.
For n = 5)determine the LU factorization for the matrix A.
2023-08-07