The function f(x) = 4 sin3x - 6 sin2x + 12 sin x + 100 is strictly:
1
increasing in\(\left(\pi, \frac{3\pi}{2}\right)\)
2
decreasing in\(\left[0, \frac{\pi}{2}\right]\)
3
decreasing in \(\left( \frac{\pi}{2},\pi\right)\)
4
decreasing in \(\left[\frac{-\pi}{2}, \frac{\pi}{2}\right]\)