NTA Abhyas JEE Main2020MathematicsIndefinite IntegrationPractice
The integral I = ∫ sec 3 ⁡ x tan 3 ⁡ x d x is equal to (where, C is the constant of integration)
Options
- Asec 5 x - sec 3 x + C
- Bsec 5 x 5 - sec 3 x + C
- Csec 5 x 5 - sec 3 x 3 + C
- Dsec 5 x 5 - tan - 1 x + C
Correct answer
C. sec 5 x 5 - sec 3 x 3 + C
Step-by-step solution
Let sec ⁡ x = t ⇒ sec ⁡ x tan ⁡ x d x = d t ∴ I = ∫ sec 2 ⁡ x tan 2 ⁡ x sec x tan x d x = ∫ t 2 t 2 - 1 d t = ∫ t 4 - t 2 d t = t 5 5 - t 3 3 + C I = sec 5 ⁡ x 5 - sec 3 ⁡ x 3 + C