Trignometry - 5

Geometry

Given that, $A_n = \sin^{n}\theta + \cos^{n}\theta$ where n is whole number and $\theta \epsilon \mathbb{R}$ .

If, $A_{n-2} - A_n =( \sin^2\theta \cos^2\theta ) A_{\lambda}$ . What is the value of $\lambda$ ?