Let f(x) be a function on Rn with continuous first-order partial derivatives and let M be a subspace of Rn. Assume that x* ∈ M.
Suppose x* minimizes f(x) on M. Prove that ∇f(x*) ∈ M⊥
Assume, in addition, that f(x) is convex and ∇f(x*) ∈ M⊥. Prove that x* is a global minimizer of f(x) on M.
Let f(x) be a function on Rn with continuous first-order partial derivatives and let M be a subsp...
Suppose that f(x) is a convex function with continuous first partials defined on a convex set C in R". Prove that a point x* in C is a global minimizer of f(x) on C if and only if Vf(x*)-(x - x*)2 0 for all x in C. Suppose that f(x) is a convex function with continuous first partials defined on a convex set C in R". Prove that a point x* in C is a global minimizer of f(x) on...
5. (a) Suppose f is any function with continuous second-order partial derivatives such that f(0,0) = 0 and (0,0) is a critical point of f. Write an expression for the second-degree Taylor polynomial, Q, of f at (0,0).
Suppose that f is a twice differentiable function and that its second partial derivatives are continuous. Let h(t) = f(x(t), y(t)) where x = 2e and y = 2t. Suppose that f:(2,0) = 4, fy(2,0) = 3, fx=(2,0) = 2, fyy(2,0) = 3, and fxy(2,0) = 2. Find out that when t=0.
Find the first-order partial derivatives (fr. f,) and second-order partial derivatives (fxxıfyy, fxy, fyx) of the following functions. a. f(x,y)=x’y+x’y? +x+y? b. f(x, y) = (x + y)? Find the critical points at which the following function may be optimized and determine whether at these points the function is maximized, minimized or at a saddle point. z = 5x2 – 3y2 – 30x + 7y + 4xy
Example: Let x, y ∈ Rn, where n ∈ N. The line segment joining x to y is the subset {(1 − t)x + ty : 0 ≤ t ≤ 1 } of R n . A subset A of Rn, where n ∈ N, is called convex if it contains the line segment joining any two of its points. It is easy to check that any convex set is path-connected. (a) Let f : X → Y be an...
Let a continuously differentiable function f: Rn → R and a point x E Rn be given. For d E Rn we define Prove the following statements: (i) If f is convex and gd has a local minimum at t-0 for every d E R", then x is a minimiser of f. (ii) In general, the statement in (i) does not hold without assuming f to be convex. Hint: For) consider the function f: R2-»R given by Let a continuously...
. M Compute all the first and second partial derivatives of the function f(x,t) = 2 COS(4+3 – 27t) af ar af at 22 a22 TO M PO 02f δεδε 02f at2 M
8. Let f and g be scalar functions with continuous partial derivatives, and let C and S satisfy the conditions of Stokes's Theorem. Verify each identity. (a) dr = Vg) N ds X (b) dr 0 (e) 8. Let f and g be scalar functions with continuous partial derivatives, and let C and S satisfy the conditions of Stokes's Theorem. Verify each identity. (a) dr = Vg) N ds X (b) dr 0 (e)
(4) Let f R -R be a strictly conve:r C2 function and let 0 a) Write the Euler-Lagrange equation for the minimizer u.(x) of the following problem: minimize u subject to: u E A, where A- 0,REC1[0 , 1and u (0 a u(1)b) b) Assuming the minimizer u(a) is a C2 function, prove t is strictly convex (4) Let f R -R be a strictly conve:r C2 function and let 0 a) Write the Euler-Lagrange equation for the minimizer u.(x)...
(8) 2 points Let f be a function defined and continuous, with continuous first partial derivative at the origin (0,0). A unit vector u for which D.f (0,0) is the maximum is: maximum a 1 (0,0)), A. /(0,0)x,0),y (0 af B. (0,0) 8x0,0),(0,0)), af 1 ((0,0),-y C. (0,0), /(0,0) D. None of the above. (8) 2 points Let f be a function defined and continuous, with continuous first partial derivative at the origin (0,0). A unit vector u for which...