Question:
Let $f_{k}(x)=\frac{1}{k}\left(\sin ^{k} x+\cos ^{k} x\right)$ where $x \in R$ and $k \geq 1$
Then $f_{4}(x)-f_{6}(x)$ equals
Correct Option: 2
JEE Main Previous Year 2014
Solution:
Let $f_{k}(x)=\frac{1}{k}\left(\sin ^{k} x+\cos ^{k} x\right)$ where $x \in R$ and $k \geq 1$
Then $f_{4}(x)-f_{6}(x)$ equals
Correct Option: 2