Trigonometry Examples

$\cos (\frac{4 π}{15}) \cos (\frac{π}{10}) + \sin (\frac{4 π}{15}) \sin (\frac{π}{10})$

Step 1

The result can be shown in multiple forms.

Exact Form:

$\cos (\frac{4 π}{15}) \cos (\frac{π}{10}) + \sin (\frac{4 π}{15}) \sin (\frac{π}{10})$

Decimal Form:

$0.86602540 \dots$