I need help with this problem! Use the Chain Rule to find dy/dt at t=9 given that y=(u+2)/(u-1), u=(3s-7)^2, and s=the square root of t.

Question

I need help with this problem!  Use the Chain Rule to find dy/dt at t=9 given that y=(u+2)/(u-1), u=(3s-7)^2, and s=the square root of t.

anonymous · Answer

The chain rule is just dy/du * du/ds * ds/dt

anonymous · Answer

So I can take the derivative of y, the derivative of u, and the derivative of s and multiply them.... and substitute 9 for t?

anonymous · Answer

After you take the derivative you'll have to plug in your values of u and s again. Then plug in t=9.

anonymous · Answer

i got dy/du=(2-u)/(u-1)  is that correct so far?

anonymous · Answer

and du/ds= 18s-42  is this correct?