If ( 1x + 1x3 ) ( [23]3x-24 + x-26 ) dx = - 3( + 1) (3x + x ) + 1 + C, x > 0, ( , , Z), where C is the constant of integration, then + + is equal to .
Answer
19
Solution
[23]3x-24 + x-26 = [23]x-23 (3x-1 + x-3 ) = 1x ( 3x + 1x3 ) 123 (as x > 0)
I = ( 1x2 + 1x4 ) ( 3x + 1x3 ) 123 dx
Put u = 3x + 1x3
du = (- 3x2 - 3x4 ) dx = -3 ( 1x2 + 1x4 ) dx
I = - 13 u 123 du = - 13 2324 u 2423 + C
= - 233(24) (3x-1 + x-3 ) 2423 + C
Comparing: = 23, = -1, = -3
+ + = 23 - 1 - 3 = 19
Answer: 19