If y = Σ k = 1 ⁶ k cos ⁻¹ 3/5 cos kx - 4/5 sin kx \, then dy/dx at x = 0 is _ _ _ _.

Limit, Continuity and Differentiability: JEE Main 2020 Mathematics question

JEE Main 2020 · 2 Sep, Evening shift · Q24

JEE Main 20202 Sep, Evening shiftMathematicsMediumLimit, Continuity and Differentiability420× since 2002

If y =

\sum\limits_{k = 1}^6 {k{{\cos }^{ - 1}}\left\{ {{3 \over 5}\cos kx - {4 \over 5}\sin kx} \right\}}

, then

{{dy} \over {dx}}

at x = 0 is _______.

Your answerType your answer. Integers and decimals are accepted.

JEE Main 2020 · 2 Sep, Evening shift · Q24

JEE Main 20202 Sep, Evening shiftMathematicsMediumLimit, Continuity and Differentiability420× since 2002

If y =

\sum\limits_{k = 1}^6 {k{{\cos }^{ - 1}}\left\{ {{3 \over 5}\cos kx - {4 \over 5}\sin kx} \right\}}

, then

{{dy} \over {dx}}

at x = 0 is _______.

Your answerType your answer. Integers and decimals are accepted.