Q. 66 - Precalculus Enhanced with Graphing Utilities

Question

Use the even–odd properties to find the exact value of each expression. Do not use a calculator.

$\cos (-{270}^{\mathrm{o}})$

Step-by-Step Solution

Answer

The exact value of the given trigonometric expression is 0.

Step 1. Given information

Given that the trigonometric expression is $\cos (-{270}^{\mathrm{o}}).$ To find the exact value of trigonometric equation using even odd property.

Step 2. Even odd property

On substituting the given expression in even odd property,

$$\begin{gathered} \cos (-\mathrm{\theta })=\mathrm{x}=\mathrm{cos\theta } \\ \cos (-{270}^{\mathrm{o}})=\cos {270}^{\mathrm{o}} \\ =\mathrm{x} \\ =0 \end{gathered}$$