# Math Help - power rule derivatives

1. ## 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.

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

thanks

2. 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.

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.

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

now continue

3. Find the derivative of the function below. Assume that a and b are constants.

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

4. Originally Posted by mer1988
Find the derivative of the function below. Assume that a and b are constants.

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?

5. Originally Posted by mer1988
alright, this one i thought i did it right, however it what wrong, i got 56ab^6q...what the did i do wrong?
Please don't swear. We get 4th graders (and maybe some younger) here.

-Dan