How many solutions exist for the equation 3Cos 2x=-3 in the interval 0<=x<=2Pi The 2 confuses me. How do I adjust for that? Thanks
$\displaystyle 3\cos(2x) = -3$
$\displaystyle \cos(2x) = -1$
since $\displaystyle 0 \leq x \leq 2\pi$ , then $\displaystyle 0 \leq 2x \leq 4\pi$
$\displaystyle 2x = \pi$
$\displaystyle x = \frac{\pi}{2}$
$\displaystyle 2x = 3\pi$
$\displaystyle x = \frac{3\pi}{2}$