NTA Abhyas JEE Main2020MathematicsIndefinite IntegrationPractice
The value of ∫ s i n 3 x cos ⁡ x d x is equal to (where, c is the constant of integration)
Options
- A2 3 cos x 3 2 + 2 7 cos x 7 2 + c
- B- 2 3 cos x 3 2 + 2 7 c o s x 7 2 + c
- C- 2 3 cos x 3 + 2 5 cos x 5 2 + c
- D3 2 cos x 3 2 + 5 2 cos x 7 2 + c
Correct answer
B. - 2 3 cos x 3 2 + 2 7 c o s x 7 2 + c
Step-by-step solution
∫ s i n 2 x cos ⁡ x sin ⁡ x d x Substituting, cos ⁡ x = t and sin ⁡ x d x = - d t = - ∫ 1 - t 2 t d t = - ∫ t 1 2 - t 5 2 d t = - t 3 2 3 2 + t 7 2 7 2 + c = - 2 3 cos ⁡ x 3 2 + 2 7 cos ⁡ x 7 2 + c