# Thread: help find this derivative: y = 1.8sin^3((pi/12)x - (pi/2)) + 98.6

1. ## help find this derivative: y = 1.8sin^3((pi/12)x - (pi/2)) + 98.6

so i've been working on some extra credit that's not due til the end of the week. My teacher said we could work with others so this isn't cheating. Right? Anyway, I cant find the derivative of y = 1.8sin^3((pi/12)x - (pi/2)) + 98.6
Sorry about the text, I cant find out how to get the pi symbol. I've tried this multiple times and can't come out to the right answer(Checked on Wolframalpha). If someone could please help I would much appreciate it.

2. Originally Posted by xN1LO
so i've been working on some extra credit that's not due til the end of the week. My teacher said we could work with others so this isn't cheating. Right? Anyway, I cant find the derivative of y = 1.8sin^3((pi/12)x - (pi/2)) + 98.6
Sorry about the text, I cant find out how to get the pi symbol. I've tried this multiple times and can't come out to the right answer(Checked on Wolframalpha). If someone could please help I would much appreciate it.
What are your thoughts? What have you done so far? Please show us your work even if you feel that it is wrong so we may try to help you. You might also read
http://www.freemathhelp.com/forum/th...Before-Posting

3. Originally Posted by xN1LO
so i've been working on some extra credit that's not due til the end of the week. My teacher said we could work with others so this isn't cheating. Right? Anyway, I cant find the derivative of y = 1.8sin^3((pi/12)x - (pi/2)) + 98.6
Sorry about the text, I cant find out how to get the pi symbol. I've tried this multiple times and can't come out to the right answer(Checked on Wolframalpha). If someone could please help I would much appreciate it.
$y = 1.8{\sin ^3}\left( {\tfrac{\pi }{{12}}x - \tfrac{\pi }{2} + 98.6} \right)$ the code is:
[ tex]y = 1.8{\sin ^3}\left( {\frac{\pi }{{12}}x - \frac{\pi }{2} + 98.6} \right)[/tex ](removing the first & last space)

If $y = C{\sin ^n}\left( {f(x)} \right)$ then $y' = nC{\sin ^{n - 1}}\left( {f(x)} \right)\cos \left( {f(x)} \right)f'(x)$.

4. Hint:

sin(Θ - π/2) = - cos(Θ)

5. Originally Posted by xN1LO
so i've been working on some extra credit that's not due til the end of the week. My teacher said we could work with others so this isn't cheating. Right?
If by "working with others" the instructor meant "getting help from complete strangers completely outside of your classmates", then possibly. But "working with others" does require the "with", so we'll need to see what you've tried so far. Only then can we help you figure out where things are going sideways.