NTA Abhyas JEE Main2020MathematicsDefinite IntegrationPractice
The value of lim n → ∞ Σ r = 1 r = 4 n n r 3 r + 4 n 2 is equal to
Options
- A1 8
- B1 10
- C1 6
- D1 9
Correct answer
B. 1 10
Step-by-step solution
lim n → ∞ Σ r = 1 r = 4 n 1 r / n 3 r n + 4 2 · 1 n = ∫ 0 4 1 x 3 x + 4 2 dx Put, 3 x + 4 = t 3 2 x dx = dt ⇒ 1 x dx = 2 3 dt when x = 0 then t = 4 when x = 4 then t = 10 = 2 3 ∫ 4 1 0 1 t 2 dt = 2 3 - 1 t 4 1 0 = - 2 3 1 1 0 - 1 4 = 1 1 0