simple calculus question help! :(

[wonsta]

its really simple calculus.. it seems really.. i just cant solve it.. guess im dumb?
i tried though just want to make sure XD
(i) consider the function y=f(x)=(c/2-x/3)x^2 where c is a positive constant
now find y' and y"

i sort of got this for f'-> 2x(c/2-x/3) is this right?!!
im so confused :S.. how to differentiate x/3?

please help!

 

[wjm11]

(i) consider the function y=f(x)=(c/2-x/3)x^2 where c is a positive constant
now find y' and y"

i sort of got this for f'-> 2x(c/2-x/3) is this right?!!
im so confused :S.. how to differentiate x/3?

Start by expanding (multiplying out):

(c/2-x/3)x^2 = (c/2)(x^2) – (1/3)(x^3)

Now just use the Power Rule.