The double angle formulae are: \(\sin 2A = 2\sin A\cos A\) \(\cos 2A = {\cos ^2}A - {\sin ^2}A\) \(= 2{\cos ^2}A - 1\) \(= 1 - 2{\sin ^2}A\) From the triangle below ...

Angle: The measure of the opening between two intersecting lines is called an angle. Unit: The unit of angle is radians or degrees. Angle formula: There are different types of formulas for calculating ...