AP EAMCET202119 Aug 2021Evening ShiftMathematicsIndefinite IntegrationActual
Which of the following is a partial fraction of - x 2 + 6 x + 13 ( 3 x + 5 ) x 2 + 4 x + 4 =
Options
- A3 3 x + 5 + − 1 x + 2 + 2 ( x + 2 ) 2
- B2 3 x + 5 + − 1 x + 2 + 3 ( x + 2 ) 2
- C− 1 3 x + 5 + 2 x + 2 + 3 ( x + 2 ) 2
- D3 3 x + 5 + 2 x + 2 + − 1 ( x + 2 ) 2
Correct answer
B. 2 3 x + 5 + − 1 x + 2 + 3 ( x + 2 ) 2
Step-by-step solution
Given, - x 2 + 6 x + 13 ( 3 x + 5 ) x 2 + 4 x + 4 = - x 2 + 6 x + 13 ( 3 x + 5 ) x + 2 2 Using Partial fraction rules, we get - x 2 + 6 x + 13 ( 3 x + 5 ) x + 2 2 = A 3 x + 5 + B x + 2 + C x + 2 2 ⇒ - x 2 + 6 x + 13 = A x + 2 2 + B x + 2 3 x + 5 + C 3 x + 5 Putting x = - 2 , we get C = 3 Putting x = - 5 3 , we get A = 2 and on comparing coefficients of x 2 , we get B = - 1 i.e. - x 2 + 6 x + 13 ( 3 x + 5 ) x + 2 2 = 2 3 x + 5 - 1 x + 2 + 3 x + 2 2