# How do you find #arcsin(-sqrt3/2)# without a calculator?

##### 2 Answers

Sep 19, 2015

First way: Use the Trig Table of Special Arcs

Second way: Use the trig unit circle.

In the triangle OMm, angle M = 60 deg ; OM = 1 unit ; Mm = 1/2.

Therefor,

sin (-60) = sin (-120) = -

Sep 19, 2015

240

#### Explanation:

Since the value of the sine is negative, it should be in the third quadrant.

As we know

Hence

Hence,

In degrees, take π radians = 180 degrees.

Hence