Precalculus Examples

$\cos (90)$

Step 1

To convert degrees to radians, multiply by $\frac{π}{180 °}$ , since a full circle is $360 °$ or $2 π$ radians.

Step 2

The exact value of $\cos (90)$ is $0$ .

$0 \cdot \frac{π}{180}$ radians

Step 3

Multiply $0$ by $\frac{π}{180}$ .

$0$ radians