- #1

Qube

Gold Member

- 468

- 1

## Homework Statement

I am having extreme trouble with the following problems:

http://i.minus.com/iYs6ix6otGtLV.png [Broken]

## Homework Equations

For 26:

If the first derivative is positive, then the function is increasing. If the first derivative is negative, then the function is decreasing.

If the second derivative is positive, then the function is concave up. If the second derivative is negative, then the function is concave down.

I tried setting (lnx)/x > 0 but I am having difficulty solving this inequality.

I also tried setting (1-lnx)/x^2 > 0 but I am having difficulty solving this inequality.

For 27:

The constant is a dummy variable, and can be ignored. I used the second fundamental theorem of calculus and substituted in 2x, getting the square root of (4x^2 - 2x). I plugged in 2 and got the square root of 12. The answer key says E. Why am I wrong?

Last edited by a moderator: