## tmagloire1 one year ago Can anyone help with this AP Calculus AB problem? Here is the picture of the question. Thanks in advanced http://prntscr.com/7u6a4c

1. anonymous

do you know the product rule?

2. tmagloire1

yes u'v(uv')

3. anonymous

you add them :) $\frac{ d(uv) }{ dx }=u'v+uv'$

4. anonymous

So you can let u = x and v = sin x

5. tmagloire1

Ohh and if i get xsinx than its true

6. anonymous

Looks like its asking you to take the 3rd derivative of x sin x and if that matches the stuff on the right it's true

7. tmagloire1

oh okay ill try it

8. tmagloire1

I got -3sinx+xcosx

9. tmagloire1

so its false

10. anonymous

I got -3 sin x - x cos x

11. tmagloire1

Oh I must have missed the negative

12. tmagloire1

So it would be true than

13. anonymous

yes

14. tmagloire1

Thank you so much!

15. anonymous

yw

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