# Systems of simultaneous trigonometric equations

At solving simultaneous trigonometric equations we use the same methods, as in algebra ( exchange, substitution, elimination etc.) and also the known methods and formulas of trigonometry. Consider some examples.

E x a m p l e 1 . Solve the system of simultaneous equations:

E x a m p l e 2 . Solve the system of simultaneous equations:

S o l u t i o n . Adding and subtracting these two equations, we receive:

Consider each of the branches of the second equation solution separately: