JEE Main202315 Apr 2023Morning ShiftMathematicsIndefinite IntegrationActual
Let f x = ∫ d x 3 + 4 x 2 4 - 3 x 2 , x < 2 3 . If f 0 = 0 and f 1 = 1 α β tan - 1 α β , α , β > 0 , then α 2 + β 2 is equal to _______.
Correct answer
0
Step-by-step solution
Given, f x = ∫ d x 3 + 4 x 2 4 - 3 x 2 Put x = 1 t ,   d x = - 1 t 2 d t So, f x = ∫ - d t t 2 3 + 4 t 2 4 - 3 t 2 ⇒ f x = ∫ - t   d t 3 t 2 + 4 4 t 2 - 3 Now let, 4 t 2 - 3 = λ 2 ⇒ 8 t   d t = 2 λ   d λ ⇒ f x = - ∫ λ   d λ 4 · 3 λ 2 + 3 4 + 4 · λ ⇒ f x = - ∫ d λ 3 λ 2 + 9 + 16 ⇒ f x = - ∫ d λ 3 λ 2 + 25 ⇒ f x = - 1 3 ∫ d λ λ 2 + 25 3 ͡