Question

Find the derivative of l(x)=4/x^2 by using the power rule.

l ' (x) = _______

so would i start like this?
4x^2-1 ?

Answer 1

actually
\[\large \frac{4}{x^2}=4x^{-2} \]
and apply the power rule for derivatives

Answer 2

ohh okay, darn.. :P so would it be like this?

(-1) * 4x^-2 = -4x^-2 = -4/x^2 ? :/

Answer 3

Multiply by the power (which is -2).

Then, reduce the power by one.

Answer 4

ohh so (-1) * 4x^2-1 = (-1) * 4x^1 = -4x ?

Answer 5

No... Read the above again :P

Answer 6

And the power is -2 NOT 2.

Answer 7

ohhh okay oops.. :P so (-1) * 4x^-2-1=(-1) * 4x^-3 = -4x^-3 = -4/x^3 ??

Answer 8

Start from scratch.

\[\large I(x) = 4x^{-2}\]

Multiply by the power (which is -2).

Then, reduce the power by one.

Answer 9

=4x^-2-1= 4x^-3 ?

Answer 10

Read the power rule again... you're skipping an entire step.

Answer 11

u have
\[\large f(x)=Kx^n \]
where K=4 and n=-2 the power rule says
\[\large f'(x)=Knx^{n-1} \]

Answer 12

oh so (4) x (-2^-2-1) ?

Answer 13

^ can't tell what you are doing...

\[\large I(x) = 4x^{-2}\]

Multiply by the power (which is -2).

Then, reduce the power by one.

\[\large I'(x) = -2* 4x^{-2-1}\]

Answer 14

ohh okay

and sorrry!! i'll try to make it neater!!
and more eligible lol :P

so -2 * 4x^ -3

=-8x^-3

= -8/x^3 ??

Answer 15

Use the equation editor, it's not too hard. You can right click what i write and copy and paste

Answer 16

yes. u got it.

Answer 17

\[I′(x)=−2∗4x−2−1 \] \[= -8/x^3\]

Answer 18

haha whoah.. never used equation tool before!! it's like latex!! haha

Answer 19

oh yayy!! :)