Question

locate the critical points and classify them as stationary points or points of nondifferentiability for f(x)=cos3x

Answer 1

derivative is \(-3\sin(3x)\)
zeros of the derivative are where \(3x=0, \pi, 2\pi,...\)

Answer 2

-so \(x=\frac{k\pi}{3}\)

Answer 3

they are clearly stationary points, since cosine is infinitely differentiable

Answer 4

oh okay i see thank you :)