Trigonometry Examples

$\cos^{2} (\frac{π}{9}) - \sin^{2} (\frac{π}{9})$

Step 1

Apply the cosine double-angle identity.

$\cos (2 \frac{π}{9})$

Step 2

Combine $2$ and $\frac{π}{9}$ .

$\cos (\frac{2 π}{9})$

Step 3

The result can be shown in multiple forms.

Exact Form:

$\cos (\frac{2 π}{9})$

Decimal Form:

$0.76604444 \dots$

$[\begin{array}{c} x^{2} & \frac{1}{2} \\ \sqrt{π} & \int x d x \end{array}]$