- #1

rsaad

- 77

- 0

for cos 2x, the critical points should be n/2 * pi - 0.25*pi

because if I set y=2x = n*pi - 0.5*pi , I get the eq in red for x.

However if I do it graphically, I just get n*pi - 0.25*pi.

The question: why algebraically I am constrained to use the even number n but graphically, there is no restriction on n?