Trigonometry Examples

$\cos (\frac{- 2}{5})$

Step 1

Move the negative in front of the fraction.

$\cos (- \frac{2}{5})$

Step 2

Since $\cos (- \frac{2}{5})$ is an even function, rewrite $\cos (- \frac{2}{5})$ as $\cos (\frac{2}{5})$ .

$\cos (\frac{2}{5})$

Step 3

The result can be shown in multiple forms.

Exact Form:

$\cos (\frac{2}{5})$

Decimal Form:

$0.92106099 \dots$