Find f ''(x) when f(x)=sinx/ x^2. Thanks

Question

Find f ''(x) when  f(x)=sinx/ x^2. Thanks

anonymous · Answer

i suggest graphing it to get your 0s

anonymous · Answer

I dont know how to do that though.

anonymous · Answer

:/ Pleasee help me with this. Ive been working on this problem for like an hour and I still can't get it. Ugh im so confused

anonymous · Answer

Rewrite this as $$\sin(x) \times x^{-2}$$

Then use the rule of taking the 1st times the derivative of the 2nd plus the 2nd times the derivative of the first. (1D2 + 2D1 is what I like to remember it by).

$$\sin(x)(-2x ^{-3)}+(x ^{-2})(-\cos(x))$$ is the first derivative.  Do the same for the second derivative now using the 1D2 + 2D1 rule for both terms.

anonymous · Answer

WHATTT?! please break it down more for me! :/

anonymous · Answer

got it!

anonymous · Answer

You sure? :)

anonymous · Answer

yuppp :D You helped me alot! you're the best <3