JEE Main2014MathematicsIndefinite IntegrationActual
The integral ^2 x ^2 x ( ^3 x+ ^3 x )^2 d x is equal to:
Options
- A1 (1+ ^3 x . +c
- B.- 1 3 (1+ ^3 x . +c )
- C^3 x (1+ ^3 x . +c
- D- ^3 x 3 (1+ ^3 x . +c
Correct answer
B. .- 1 3 (1+ ^3 x . +c )
Step-by-step solution
Let I= ^2 x ^2 x ( ^3 x+ ^3 x )^2 d x aligned & I = ( x x ^3 x+ ^3 x )^2 d x & I = ( x x ^3 x (1+ ^3 x ) )^2 d x &= ( x ^2 x (1+ ^3 x ) )^2 d x & Put 1+ ^3 x= t &d t=3 ^2 x ^2 x d x or d x &= d t 3 ^2 x ^2 x & I = ^2 x ^4 x t^2 d t 3 ^2 x ^2 x aligned aligned & I = 1 3 ^2 x ^4 x t^2 d t ^2 x ^2 x ^2 x &= 1 3 ^2 x ^4 x t^2 d t ^2 x ^4 x & I = 1 3 d t t^2 = 1 3 t⁻² d t & I = 1 3 [ t⁻²⁺¹ -2+1 ]+c= -1 3 [ 1 t ]+c & or I =- 1 3 (1+ ^3 x ) +c aligned