# power rule derivatives

• Sep 24th 2007, 08:05 PM
mer1988
power rule derivatives
ok I've done this one but cant seem to get the right answer, what am i doing wrong?

Find the derivative of the function below.
http://www.webassign.net/www31/symIm...ab0768f819.gif

i got...2x-7x^(-2)

thanks
• Sep 24th 2007, 08:08 PM
Jhevon
Quote:

Originally Posted by mer1988
ok I've done this one but cant seem to get the right answer, what am i doing wrong?

Find the derivative of the function below.
http://www.webassign.net/www31/symIm...ab0768f819.gif

thanks

what problems are you having with changing these forms to forms with powers? if you don't understand the manipulations i or some other users do, it is in your best interest to ask. based on the problems you've received help with thus far, you should not be having a problem with this.

$\displaystyle h(x) = x^2 + \frac 1{7x} = x^2 + \frac 17x^{-1}$

now continue
• Sep 24th 2007, 08:49 PM
mer1988
Find the derivative of the function below. Assume that a and b are constants.
http://www.webassign.net/www15/symIm...22dbed58fb.gif

alright, this one i thought i did it right, however it what wrong, i got 56ab^6q...what did i do wrong?
• Sep 24th 2007, 08:58 PM
ticbol
Quote:

Originally Posted by mer1988
Find the derivative of the function below. Assume that a and b are constants.
http://www.webassign.net/www15/symIm...22dbed58fb.gif

alright, this one i thought i did it right, however it what wrong, i got 56ab^6q...what did i do wrong?

If b is assumed constant, then why did you differentiate it? You cannot differentiate constants.

w = (8ab^7)q
dw/dq = 8ab^7

If y = 3x
What is dy/dx?
• Sep 25th 2007, 05:29 AM
topsquark
Quote:

Originally Posted by mer1988
alright, this one i thought i did it right, however it what wrong, i got 56ab^6q...what the (Swear) did i do wrong?

Please don't swear. We get 4th graders (and maybe some younger) here.

-Dan