JEE Main20204 Sep 2020Morning ShiftMathematicsIndefinite IntegrationActual
The integral ∫ x x sin x + cos x 2 d x is equal to, (where C is a constant of integration):
Options
- Atan x - x sec x x sin x + cos x + C
- Bsec x + x tan x x sin x + cos x + C
- Csec x - x tan x x sin x + cos x + C
- Dtan x + x sec x x sin x + cos x + C
Correct answer
A. tan x - x sec x x sin x + cos x + C
Step-by-step solution
∫ x 2      d x x sin x + cos x 2 = ∫ x cos x ⋅ x cos x x sin x + cos x 2   d x = x cos x ∫ x cos x x sin x + cos x 2 d x − ∫ d d x x sec x ∫ x cos x x sin x + cos x 2   d x   d x = x cos x − 1 x sin x + cos x + ∫ sec 2 x    d x , ∵     ∫ x cos x x sin x + cos x 2 d x = − 1 x sin x + cos x   &   d d x x sec x = sec x + x sec x tan x = sec x 1 + x sin x co