17.47 Use Problems
Condition: Solve the following equation by lowering the degree. \ [\ cos ^{6} x- \ sin ^{6} x = \ frac {13} {8} \ cos ^{2} 2 x \]
Problems of the Use (Unified state Exam) - Equations and Inequalites in Terms of A Parameter, Solved Both by Algebraic Methods and Geometric One.