Question

In the interval $[-2\pi ,2\pi ],\sin x=-1\text{or}1$ for which of the following?

• A. $x=\frac{3\pi }{2}$
• B. $x=\frac{-3\pi }{2}$
• C. $x=\frac{-5\pi }{2}$
• D. $x=\frac{-\pi }{2}$

Answer 1

Answer: (A), (B), (D)

$x=\frac{-\pi }{2}$

From the graph of $\sin x$,

we see that $\sin x=1\text{or}-1$ in the required interval when $x=\frac{-3\pi }{2},\frac{-\pi }{2},\frac{\pi }{2},\frac{3\pi }{2}$