# Recent questions tagged trigonometry

For $0 \leq x \leq 2\pi$, $\sin x$ and $\cos x$ are both decreasing functions in the interval __________. $\bigg( 0, \dfrac{\pi}{2} \bigg) \\$ $\bigg( \dfrac{\pi}{2}, \pi \bigg) \\$ $\bigg( \pi, \dfrac{3\pi}{2} \bigg) \\$ $\bigg(\dfrac{3 \pi}{2}, 2 \pi \bigg)$
Which one of the following is the solution for $\cos^2 x + 2 \cos x + 1 = 0$, for values of $x$ in the range of $0^\circ < x < 360^\circ$ $45^\circ$ $90^\circ$ $180^\circ$ $270^\circ$