# Thread: Need help in finding the maximum

1. ## Need help in finding the maximum

I need help in finding the maximum of this equation:
V(t)=2580+300cos(t*138.23007)

I found the derivative to be:
V'(t)=-41469.02100*sin(138.23007*t)

2. Originally Posted by Theressa
I need help in finding the maximum of this equation:
V(t)=2580+300cos(w*138.23007)

I found the derivative to be:
V'(t)=-41469.02100*sin(138.23007*t)

As you can see, in the definition of V(t) there is no t in the right hand, so its derivative would be zero!
I'm sure there's a typo somewhere but I can't say where.

Tonio

3. Originally Posted by tonio
As you can see, in the definition of V(t) there is no t in the right hand, so its derivative would be zero!
I'm sure there's a typo somewhere but I can't say where.

Tonio
Sorry about that, the w is supposed to be a t. My mistake.

4. Originally Posted by Theressa
I need help in finding the maximum of this equation:
V(t)=2580+300cos(t*138.23007)

I found the derivative to be:
V'(t)=-41469.02100*sin(138.23007*t)

$V'(t)=-41,469.021*\sin (138.23007t)=0 \Longrightarrow138.23007t=n\pi$, for some integer multiple of $\pi$ , so $t=\frac{n\pi}{138.23007}$