5. Prove that for n e Z, n is even, if and only if n2 is even. 6. Verify by induction that 3" > 2n? n>0.
Problem (2), 10 points Let n be an integer. Prove that if 3 does not divide n, then 3(2n2 5) Problem (2), 10 points Let n be an integer. Prove that if 3 does not divide n, then 3(2n2 5)
0 and 0, and let a E Z. Prove that [a],m C [a]n if and only if n | Let m,EN with m TT 0 and 0, and let a E Z. Prove that [a],m C [a]n if and only if n | Let m,EN with m TT
2a) Let a, b e R with a < b and let g [a, bR be continuous. Show that g(x) cos(nx) dx→ 0 n →oo. as Hint: Let ε > 0, By uniform continuity of g, there exists δ > 0 such that 2(b - a Choose points a = xo < x1 < . . . < Xm such that Irh-1-2k| < δ. Then we may write rb g (z) cos(nx) dx = An + Bn where 7m (g(x)...
(2) For an integer n, let Z/nZ denote the set of equivalence classes [k) tez: k -é is divisible by n (a) Prove that the set Z/nZ has n elements. (b) Find a minimal set of representatives for these n elements. (c) Prove that the operation gives a well-defined addition on Z/nZ Hint: The operution should not depend on the choice of coset representatives Verify that this gives Z/n2 the structure of an ahelian group. Be sure to verify all...
27. (a) Let m and n be integers > 1 which are relatively prime. Show that the map f : Z → Z/mZ × Z/nZ whith f(x) = (x + mZ, x + nZ) is surjective (b) Prove the Chinese Remainder Theorem: If m and n are relatively prime integers > 1 and if a and b are any integers, then there exists a E Z such that b(mod n). a(mod m) and a a Hint: (a)] 27. (a) Let...
4. Let {Sn, n > 0} be a symmetric Random Walk on Z. with So-0. Defined Y max{Sk, 1 Sk n, for n 2 0, prove, thanks to a counterexample, that Y is not a Markov Chain.
4. Let Z ~ N(0,1) be a standard normal variable. Calculate the probability (a) P(1 <Z < 2). (b) P(-0.25 < < < 0.8). (c) P(Z = 0). (d) P(Z > -1).
(4) Let f(x) (0 if x<0 (a) Show that f is differentiable at z (b) Is f'continuous on R? Is f continuous on R? Justify your answer.
2.21 Let Q(2) = VI, which is defined for all x > 0. Prove: Q E C[0,0). (Hint: If a > 0, and € > 0, we seek 6 >0 such that 3 > 0 and - al <& implies Q(x) - Q(a) < €. Begin by showing that|vx-Val' <lt - al.)