Q.

Let I(x)=dx(x11)1113(x+15)1513. If I(37)I(24)=14(1b1131c113), b, cN, then 3(b + c) is equal to          [2025]

1 39  
2 22  
3 40  
4 26  

Ans.

(1)

Given, I(x)=dx(x11)11/13(x+15)15/13

Let x11x+15=t  26dx(x+15)2=dt

  I(x)=126dt(t)11/13

                  =126×t2/13213+C

                   =14t2/13+C

  I(x)=14(x11x+15)2/13+C

  I(37)I(24)=14[(12)2/13(13)2/13]

14(1b1/131c1/13)=14(1(4)1/13191/13)

   b = 4 and c = 9

   3(b + c) = 3(4 + 9) = 39.