(4 pts) Choose the true statement. Let a,b,c e Z with a #0. If a|(b + c) and a|bc, then a|(+ c´). Let a,b,c e Z with a +0. If a|(62 +c), then a|(b+c). Let a, b, ce Z with a + 0. If a|(b+c), then aſb or a|c. Let a,b,c e Z with a +0. If a|(62 +c) and a|(b+c?), then a|(+ c´). the four other possible answers are false
2. Let a,b,c E Z. Prove the following. If aſb then g.c.d(b, c) = 1 implies g.c.d(a, c) = 1.
Let f, g E H(C) be such that |f(z)| < \g(z)| for any z e C. Show that there exists a E D(0,1) such that f(z) = ag(z) for any z E C. (Hint: consider f/g and be careful with the zeros of g.)
Let f(z) e-1/2.2 for xメ0, f(0) = 0. (a) Show that the derivative fk (0) exists for all k 21. So, f is Coo everywhere on R. b) Show that the Taylor series of f about p -0 converges everywhere on R but that it represents f only at the origin.
4. (a) Let A [0, oo) and let f.g:AR be functions which are continuous at 0 and are such that f(0) 9(0)-1. Show that there exists some δ > 0 such that ifTE 0,d) then (b) Consider the function 0 l if z e R is rational, if zER is irrational f(z) Show that limfr) does not exists for any ceR. 4. (a) Let A [0, oo) and let f.g:AR be functions which are continuous at 0 and are such...
3. (6 points) Disprove the following: For all a, b, c E Z, if aſbc, then aſb or b|c.
3. Let a, b, c E Z such that ca and (a,b) = 1. Show that (c, b) = 1. 4. Suppose a, b, c, d, e E Z such that e (a - b) and e| (c,d). Show that e (ad — bc). 5. Fix a, b E Z. Consider the statements P: (a, b) = 1, and Q: there exists x, y E Z so that ax + by = 1. Bézout’s lemma states that: if P, then...
1(a) Let f : R2 → R b constant M > 0 such that livf(x,y)|| (0.0)-0. Assume that there exists a e continuously differentiable, with Mv/r2 + уг, for all (z. y) E R2 If(x,y)| 〈 M(x2 + y2)· for all (a·y) E R2 Prove that: 1(a) Let f : R2 → R b constant M > 0 such that livf(x,y)|| (0.0)-0. Assume that there exists a e continuously differentiable, with Mv/r2 + уг, for all (z. y) E R2...
5. Let AE Maxn(C). Recall that A is said to be nilpo tent if there exists a positive integer k such that A 0. Prove the following statements (a) If A is nilpotent, then A 0. (Hint: First show that if A is nilpotent, then the Jordan form of A is also nilpotent.) (b) If A is nilpotent, then tr(A) 0 (e) A is nilpotent if and only if the characteristic polynomial of A is (-1)"" (d) If A is...
1. Let U C IRt be open, UR be a function, a U and 0 A v E R" such that Dof(a) exists. Show that DAvf(a) exists for every 0 λ E R, and DAwf(a-λDuf(a). 3 marks 1. Let U C IRt be open, UR be a function, a U and 0 A v E R" such that Dof(a) exists. Show that DAvf(a) exists for every 0 λ E R, and DAwf(a-λDuf(a). 3 marks