Wednesday
April 23, 2014

Homework Help: local min

Posted by Jen on Sunday, November 19, 2006 at 5:11pm.

f(x) = x^4 + ax^2
What is a if f(x) has a local minimum at x=5.
How do I justify the answer.

The first derivative has to be zero at x = 5. You then check what the second derivative is at x = 5. If it is positive then that's ok.

In this case you find that a = -50 and that the second derivative at x = 5 is positive.

Answer this Question

First Name:
School Subject:
Answer:

Related Questions

Calculus - Functions? - #1. A cubic polynomial function f is defined by f(x) = ...
Calculus (pleas help!!!) - Let p(x)=x^2(a−x), where a is constant and a ...
Math - need to classify to stationary points as local minimum and local maximum ...
Math - find any stationary points of the function g(x) = (2x-3)square root of 5+...
Math - What values of a and b make f(x) = x^3 + ax^2 + bx have a local max at x...
math - find the values of a and b if the function y=2x^3+ax^2+bx+36 has a local ...
how to sketch a graph of.. - Local minimum and local maximum imply that the ...
Math-Graphs - graph g(x)=4(x^3)-24x+9 on a calulator and estimate the local ...
12th Calculus - use the derivative of the function y=f(x)to find the points at ...
Calculus - I'm desperate.. I keep getting b=0 and I know it's wrong!! Find a ...

Search
Members