Use the fact that the trigonometric functions are periodic to find the exact value of the expression. Do not use a calculator.
-$\sin 495 ^ { \circ }$
A) $\frac { \sqrt { 2 } } { 2 }$
B) $- \frac { \sqrt { 2 } } { 2 }$
C) $- \frac { 1 } { 2 }$
D) $\frac { 1 } { 2 }$

Question

Quizplus · Accepted Answer

The sine function has a period of $360^\circ$, so $\sin 495^\circ = \sin (495^\circ - 360^\circ) = \sin 135^\circ$. Since $\sin 135^\circ = \frac{\sqrt{2}}{2}$, the correct answer is A.

Use the Fact That the Trigonometric Functions Are Periodic to Find