Starting with the cofunction identities, the sine addition formula is derived by applying the cosine difference formula. There are two main differences from the cosine formula: (1) the sine addition formula adds both terms, where the cosine addition formula subtracts and the subtraction formula adds; and (2) the sine formulas have sin-sin and cos-cos. Both formulas find values for angles.
Sample Problems (3)
Need help with "The Sine Addition Formulas" problems? Watch expert teachers solve similar problems to develop your skills.