Question

The general solution of the trigonometric equation $\sin x = \pm \sqrt{\frac{2}{5}}$ is.

• A. $x = n\pi$
• B. $\cos 3x + \sin\ \left( 2x - \frac{7\pi}{6} \right) = - 2$
• C. $\Rightarrow$
• D. $1 + \cos 3x + 1 + \sin\left( 2x - \frac{7\pi}{6} \right) = 0$

Answer 1

Answer: (A)

$x = n\pi$

Answer 2

$\Rightarrow \tan\theta + \cot\theta = 2$ $\Rightarrow$ $\sin 2\theta = 1 = \sin\frac{\pi}{2} \Rightarrow \theta = n\pi + \frac{\pi}{4}$.