MathematicsEasy175×since 2002Q2724Let f(x)=2cos−1x+4cot−1x−3x2−2x+10f(x) = 2{\cos ^{ - 1}}x + 4{\cot ^{ - 1}}x - 3{x^2} - 2x + 10f(x)=2cos−1x+4cot−1x−3x2−2x+10, x∈[−1,1]x \in [ - 1,1]x∈[−1,1]. If [a, b] is the range of the function f, then 4a −-− b is equal to :A11B11 −-− π\piπC11 + π\piπD15 −-− π\piπCheck answerSkip