Algebra Examples

$\cos (\frac{3 π}{7}) \cos (\frac{9 π}{28}) - \sin (\frac{3 π}{7}) \sin (\frac{9 π}{28})$

Step 1

Nothing further can be done with this topic. Please check the expression entered or try another topic.

$\cos (\frac{3 π}{7}) \cos (\frac{9 π}{28}) - \sin (\frac{3 π}{7}) \sin (\frac{9 π}{28})$