Question

How do you find the derivative of `V(t) = 156 cos(120πt)`?

Answer 1

`V'(t)=-18720pisin(120pit)`

Explanation:

V(t)= 156cos(120pit)

since we know that if `y = cosx`, then `dy/dx = -sinx`
and since the `t` in `sin` is multiplied by `120pi`, we multiply the whole term by `120pi`.
`V'(t)= -156sin(120pit)(120pi)`

therefore: `V'(t)=-18720pisin(120pit)`