Trigonometry Examples

$\cos (- \frac{π}{4})$

Step 1

Find the value using the definition of cosine.

$\cos (- \frac{π}{4}) = \frac{adjacent}{hypotenuse}$

Step 2

Substitute the values into the definition.

$\cos (- \frac{π}{4}) = \frac{\frac{\sqrt{2}}{2}}{1}$

Step 3

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

$\frac{\sqrt{2}}{2}$

Step 4

The result can be shown in multiple forms.

Exact Form:

$\frac{\sqrt{2}}{2}$

Decimal Form:

$0.70710678 \dots$

Step 5