Trigonometry Examples

$1 - 2 \sin^{2} (\frac{π}{5})$

Step 1

Apply the cosine double-angle identity.

$\cos (2 \frac{π}{5})$

Step 2

Combine $2$ and $\frac{π}{5}$ .

$\cos (\frac{2 π}{5})$

Step 3

The result can be shown in multiple forms.

Exact Form:

$\cos (\frac{2 π}{5})$

Decimal Form:

$0.30901699 \dots$

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