MATH 156, Fall 2022, Written Assignment 5
Hello, dear friend, you can consult us at any time if you have any questions, add WeChat: daixieit
MATH 156, Fall 2022, Written Assignment 5
1. [2+3=5 points] For the function
f(x,y) = ln(1 + x2 + y2 )
(a) Find all critical points.
(b) Use the second derivative test to clarify the nature of each point, if possible.
2. [2+3=5 points] Calculate the given integral using two different ways \ \0 1/4 sin(πx)cos(πy)dxdy
(a) Using one or more special cases.
(b) Not using special cases formulas.
3. [5 points] Given that f is a differentiable function with f(2, 5) = 10,f”(2, 5) = 1, and fy (2, 5) = − 1, use a total differential to estimate f(2.1, 4.8)
4. [5 points] A company finds that it takes x units of labour and y units of capital to produce
f(x,y) = 100x3/4y1/4
engines. A unit of labour costs $100 and a unit of capital costs $200. The company has decided to manufacture 2,000 engines. Find the amount of money they should spend on labout and capital to minimize their production cost.
2022-10-25