3-4 Points) Let R be an arbitrary ring and z, y R. Show that x2-y- (x...
1. Let R be a commutative ring with identity and let u e R be nilpotent elements a) (3 pt) Show that x + y and xy are nilpotent elements. b) (3 pt) Show that if u is a unit of R and t is nilpotent, then u is a umit. ) 3 pt) Show that if R is not commutative, neither of the above necessarily holds (r t y is not necessarily nilpotent and u 4- r is not...
5. (7 points) Let f: R3 → R be the function f(x,y,z) = x2 + y2 +3(2-1)2 Let EC R3 be the closed half-ball E = {(x, y, z) e R$: x² + y2 +< 9 and 2 >0}. Find all the points (x, y, z) at which f attains its global maximum and minimum on E.
8. Let V = {(x,y)x,y e R}. Define addition on V as follows: (x,x)+(x2,)=(x, +x,-1,, +y,+3) [4 marks] a. Prove addition axiom #3 (Addition is commutative). b. Find the zero vector.
#1 & 2
Exercise 2.121 Let R be a ring. Definition 2.121.1 The center of R, written Z(R), is defined to be the set {re R | rx = xr for all x € R}. 1. Show that Z(R) is a subring of R. 2. If R is commutative, what is Z(R)?
just 10 thank you
9) Let R and S be commutative rings. Show that the cartesian product is a ring with addition and multiplication s') := (r , rrs-s' ) . 10) Let T be a commutative ring containing elements e, f, both 07-such that e+f=h,e=e,f2 = f , and e-f=0T . Show that the ideals R: T e and S T.f are rings but not subrings of T, and that the ring T is isomorphic to the ring R...
4. Let = 0 , 4r + 2y+-2). M={(x,y,z) € R' | - Show that A/ is a one dimensional manifold and find the maximum and minimum values of SIM where f(x,y, z) = ry + z.
4. Let = 0 , 4r + 2y+-2). M={(x,y,z) € R' | - Show that A/ is a one dimensional manifold and find the maximum and minimum values of SIM where f(x,y, z) = ry + z.
Help me with the C) please! Only the third one
1. Let R be a commutative ring of characteristic p, a prime a) Prove that (y)y. [3] b) Deduce that the map фр: R-+ R, фр(x)-z", is a ring homomorphism. 1] c) Compute Op in the case R is the ring Zp. [2] d) Prove that фр is injective if R has no zero-divisors. [2] e) Give an example of a commutative ring of characteristic p such that фр is...
Problem 4. (i) Let R> 2/14Z and consider the polynomial ring R[d]. Let A(z) 4 + 2r3 + 3r2 + 4x + 5 and B(x) 37 be elements of R]. Find q(x) and r(x) in R] such that: A(x)-q(z)E(z) + r(z) and deg(r) < 2. (2pts) (ii) Let R- Z/11Z, write down the table of squares in R as follows. For every a E R (there are 11 such elements), find a2. Here you are required to express the final...
9. (10 points) Let R be a ring and let X be a subset of R. De X Prove that A(X) is a subring of R and give an example to show that A Ir e R: r be an ideal in R. x) need not
6. Let R be a non-trivial ring with unity. Suppose x E R satisfies x2 = 0. Show that x – 1 and x +1 are units in R.