JEE Main201912 Jan 2019Morning ShiftMathematicsContinuity and DifferentiabilityActual
Let S be the set of all points in - π , π at which the function, f x = min sin x , cos x is not differentiable. Then S is a subset of which of the following?
Options
- A- 3 π 4 , - π 2 , π 2 , 3 π 4
- B- 3 π 4 , - π 4 , 3 π 4 , π 4
- C- π 4 , 0 , π 4
- D- π 2 , - π 4 ,   π 4 ,   π 2
Correct answer
B. - 3 π 4 , - π 4 , 3 π 4 , π 4
Step-by-step solution
Sharp points are at - 3 π 4 and π 4 . ∴ Set of non-differentiable points of function are - 3 π 4 , π 4 which is a subset of - 3 π 4 , - π 4 ,   3 π 4 ,   π 4 .