# JEE-Mains 2014 (28/30)

Geometry Level 2

Let $$f_k(x)=\frac{1}{k} (\sin^kx+\cos^kx$$) where $$x \in \mathbb{R}$$ and $$k \geq 1$$. What is the value of $$f_4(x)-f_6(x)$$?

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