Mht CetTrigonometric Ratios And IdentitiesMHT CET 2026 18th April Evening ShiftMCQ+2 / -02026Let $f_k(x) = \dfrac{1}{k}(\cos^k x + \sin^k x)$ where $k \in N$, then $f_6(x) - f_4(x) = \ldots$A$\dfrac{1}{6}$B$-\dfrac{1}{12}$C$-\dfrac{1}{6}$D$\dfrac{1}{12}$Check AnswerClear SelectionReveal AnswerShow Explanation