Trigonometry Examples

$\cos (\frac{- 15 π}{14})$

Step 1

Move the negative in front of the fraction.

$\cos (- \frac{15 π}{14})$

Step 2

Add full rotations of $2 π$ until the angle is greater than or equal to $0$ and less than $2 π$ .

$\cos (\frac{13 π}{14})$

Step 3

The result can be shown in multiple forms.

Exact Form:

$\cos (\frac{13 π}{14})$

Decimal Form:

$- 0.97492791 \dots$