Practice Final Examination 3 – Math 142B
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Practice Final Examination 3 – Math 142B
Question 1. Determine whether each of the following statements is true or false. No justification is required.
(a) |
If 对 an diverges, then so does 对 sin(an ). |
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(b) |
If 对 sin(an ) converges, then 对 an converges. |
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(c) |
If 对 an converges, then so does 对 an(n) . |
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(d) |
If f is an integrable function on R andla(b) f = 0 for all a,b ∈ R, then f = 0. |
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(e) |
Let P be a partition of [a,b] and R(f,P) a Riemann sum for f on [a,b] with partition P . Then U(f,P) ≥ R(f,P) ≥ L(f,P). |
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(f) |
It is possible to find partitions P and Q of [a,b] and an integrable function f on [a,b] such that L(f,P) ≥ U(f,Q). |
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(g) |
Let f(x) = x if x ∈ [0, 1] is rational and f(x) = −x if x ∈ [0, 1] is |
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(h) |
in(对)k(n)1(1))xk (1 − x)n −k uniformly approxi- |
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(i) |
Let fn (x) = n/(nx + 1) for 0 ≤ x ≤ 1. Then limn→∞ l01 fn exists. |
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(j) |
There exists a partition P of [0, 1] with parts [ai ,ai+1] for 1 ≤ i ≤ n such that 对(ai+1/ai − 1) converges as n → ∞ . |
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Question 2. Let f(北) = (sin 北)/北 for 北 0 and f(0) = 1.
(a) Determine the Taylor series T(北) for 北f(北) about 北 = 0. (b) Determine the values of 北 such that 北f(北) = T(北).
(c) Write down the Taylor series for f(北) about 北 = 0.
(d) Prove with justification that for all 北 ∈ R,
\0 x dt = (22(北)
Question 3.
Determine with justification which of the following series converges.
(a) 对 1/(n +^n).
(b) 对(− 1)n (^n + 1 − ^n).
(c) 对(^n + 1 − ^n).
(e) 对 sin .
Question 4.
Let f be a continuous function on R and let for 北 ≥ 1:
g(北) = \ f(t)dt
(a) Prove that g is differentiable on [1, ∞).
(b) Determine g\ (北).
(c) Check your answer in (b) when f(t) = t2 .
2022-09-01