KCET2015MathematicsVector Algebra
( 1 x² (x⁴+1 )^ 3 / 4 dx ) is equal to
Options
- A( - (1+x⁴ )^ 1 / 4 x +C )
- B( - (1+x⁴ )^ 1 / 4 x² +C )
- C( - (1+x⁴ )^ 1 / 4 2 x +C )
- D( - (1+x⁴ )^ 3 / 4 x +C )
Correct answer
A. ( - (1+x⁴ )^ 1 / 4 x +C )
Step-by-step solution
Given that ( I= d x x² (x⁴+1 )^ 3 / 4 ) ( = d x x² [x⁴ (1+ 1 x⁴ ) ]^ 3 / 4 ) ( = d x x² x³ (1+x⁻⁴ )^ 3 / 4 = x⁻⁵ (1+x⁻⁴ )^ 3 / 4 d x ) Let ( 1+x⁻⁴=t⁴ ) then ( -4 x⁵ d x=4 t³ d t ) So, ( I=- 1 4 4 t³ t³ d t=- d t=-t ) ( =- (1+ 1 x⁴ )^ 1 / 4 =- ( 1+x⁴ x⁴ )^ 1 / 4 =- (1+x⁴ )^ 1 / 4 x +C )