Previous Next

The following formulas relate the products of sines and cosines to sines and cosines of multiple angles. These formulas are derived from the addition formulas. They are useful identities for simplification.

sin(α)sin(β) = - (cos(α + β) - cos(α - β))    

cos(α)cos(β) = (cos(α + β) + cos(α - β))    

sin(α)cos(β) = (sin(α + β) + sin(α - β))    

cos(α)sin(β) = (sin(α + β) - sin(α - β))    

Previous section Next section

Take a Study Break