1. Let U с Rn be open, f : U-> Rm be a function, a є U and 0 exists. Show that DAwf(a) exists for every 0メλ R, and DAwf(a) Rn such that Duf(a) λDuf(a). 3 marks 1. Let U с Rn be open, f : U-&...
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
Let U be an open subset of R. Let f: U C Rn → Rm. (a) Prove that f is continuously differentiable if and only if for each a є U, for each E > 0, there exists δ > 0 such that for each x E U, if IIx-all < δ, then llDf(x)-Df(a) ll < ε. (b) Let m n. Prove that if f is continuously differentiable, a E U, and Df (a) is invertible, then there exists δ...
Let A be an m × n matrix, let x Rn and let 0 be the zero vector in Rm. (a) Let u, v є Rn be any two solutions of Ax 0, and let c E R. Use the properties of matrix-vector multiplication to show that u+v and cu are also solutions of Ax O. (b) Extend the result of (a) to show that the linear combination cu + dv is a solution of Ax 0 for any c,d...
A function f : Rn λε [0,1] R is strictly convex if for all x, y є Rn and all fax + (1-λ)y) < λ/(x) + (1-1)f(y) A symmetric matrix P-AT +A is called positive-definite if all its eigenvalues are positive. Show that a quadratic function f(x) -xPx is a convex function if and only P is positive-definite. A function f : Rn λε [0,1] R is strictly convex if for all x, y є Rn and all fax +...
Let U be an open subset of R". Let f: UCR" ->Rm. (a) Prove that f is continuously differentiable if and only if for each a e U, for eache > 0, there exists o > 0 such that for each xe U, if ||x - a| << ô, then |Df (x) Df(a)| < e.
Let U be an open subset of R". Let f:UCR"-R be differentiable at a E U. In this exercise you will prove that if ▽f(a) 0, then at the point a, the function f increases fastest in the direction of V f(a), and the maximum rate of increase is Vf(a)l (a) Prove that for each unit vector u e R" (b) Prove that if ▽/(a)メ0, and u = ▽f(a)/IV/(a) 11, then Let U be an open subset of R". Let...
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.
if (r.y) (0,0), 0,f (, y) (0, 0) 2. Consider f : IR2 -R defined by f(r,y)-+ (a) Show by explicit computation that the directional derivative exists at (x, y)- (0,0) for all oi rections u є R2 with 1 11-1, but that its value %(0.0) (Vf(0,0).u), fr at least one sucli u. (b) Show that the partial derivatives of f are not continuous at (0,0) if (r.y) (0,0), 0,f (, y) (0, 0) 2. Consider f : IR2 -R...
a set function, λ on S by λ((a, b) F(b)--F(a) and λ(0) 1. Show that if Eİ, E2 E S then Ei n E2 ES and Ei ~ E2 is a finite disjoint union of 0. sets in S 2. Show that the o-algebra generated by S is the Borel o-algebra on R. 3. Show that if E and Ea are disjoint sets in S and A U S, then (A) A(E)+A(B2). 4, Show that if E. .. ova natn...
Please prove Problem 11 & 12 carefully (note that m represents Lebesgue measure & m* represents Lebesgue outer measure): 11. Let E c Rn be an arbitrary subset. Show that for all є > 0 there exists an open set G containing E with m(G) m"(E) +e. 12. Let E C Rn be a measurable subset. Show that for all € > 0 there exists an open set G containing Ewith m (G\ E) < є. 11. Let E c...