Precalculus Examples

$\cos (\frac{π}{5}) \cos (\frac{π}{7}) + \sin (\frac{π}{5}) \sin (\frac{π}{7})$

Step 1

The result can be shown in multiple forms.

Exact Form:

$\cos (\frac{π}{5}) \cos (\frac{π}{7}) + \sin (\frac{π}{5}) \sin (\frac{π}{7})$

Decimal Form:

$0.98392958 \dots$