Chapter 13.8, Problem 73STP

To determine

Calculate the exact value of the expression.

Answer to Problem 73STP

The exact value is $-\frac{1}{2}$ .

Explanation of Solution

Given: It is given in the question that the expression is $\sin (-{30}^{\circ })$ .

Concept Used:

In this, use the concept of trigonometric function and knowing the different signs of the four quadrant.

Calculation:

Here,

  $\begin{array}{l}\sin (-{30}^{\circ })\\ -\sin {30}^{\circ }[\sin (-\theta )=-\sin \theta ]\\ -\frac{1}{2}\end{array}$

Conclusion:

The value is $-\frac{1}{2}$ .