Saturday
November 22, 2014

Homework Help: Calculus

Posted by Anonymous on Tuesday, June 1, 2010 at 6:30pm.

For y=(1/4)x^4-(2/3)x^3+(1/2)x^2-3, find the exact intervals on which the function is

a. increasing
b. decreasing
c. concave up
d. concave down
Then find any
e. local extreme values
f. inflection points

---

I thought it'd be better to find extreme values first, then you can find the points where the function is increasing or decreasing. (I'll worry about concavity and inflection points later, since that's second derivative)

So I found y':
x^3-2x^2-x
...and set it equal to zero to find the points where derivative crosses the x-axis
x^3-2x^2-x=0
I factored and used the quadratic formula, and got (2+sqrt8)/2 and (2-sqrt8)/2, or -.414 and 2.414. Oh, and zero too because I factored out an x.

So my problem is that the answers (which were given to me ahead of time to check my work) don't match my work. Apparently y is increasing from [0, infinity) and decreasing from (-infinity, 0], and none of the points I found from finding y'.

Can you find what I did wrong?

Thanks!

Answer this Question

First Name:
School Subject:
Answer:

Related Questions

grade 12 AP calculus - for f(x= -1/4x4-1/3x3+2x, use analytic method to find the...
increasing decreasing and more - How to analytically find the intervals on which...
Math - For y= (3x)/(2e^x+e^-1), use graphing techniques to find the approximate ...
calculus - Given f(x)=sin(x)-2cos(x) on the interval [0,2pi]. a) Determine where...
Calculus - For f(x)=2(x+5)^3 +7 Find and classify the extreme values, determine ...
calculus - Consider the exponential function . Which of the following best ...
Calculus - let f(x)=x^3(e^-x) Answer using calculus, use graphing calculator ...
Calculus (urgent!!) - Please answer the following questions about the function f...
Calculus (pleas help!!!) - Please answer the following questions about the ...
Calculus (pleas help!!!) - Please answer the following questions about the ...

Search
Members