Trigonometry Examples

$\cos (\frac{2 π}{3})$

Step 1

Find the value using the definition of cosine.

$\cos (\frac{2 π}{3}) = \frac{adjacent}{hypotenuse}$

Step 2

Substitute the values into the definition.

$\cos (\frac{2 π}{3}) = \frac{- \frac{1}{2}}{1}$

Step 3

Divide $- \frac{1}{2}$ by $1$ .

$- \frac{1}{2}$

Step 4