The integral 0 /4 136 x3 x + 5 x dx is equal to :
- 3 - 50 e 2 + 20 e 5
- 3 - 25 e 2 + 10 e 5
- 3 - 10 e(2 2) + 10 e 5
- 3 - 30 e 2 + 20 e 5
Answer
(1) 3 - 50 e 2 + 20 e 5
Solution
Numerator = A(Denominator) + B(derivative of Denominator):
136 x = A(3 x + 5 x) + B(3 x - 5 x)
3A - 5B = 136, 5A + 3B = 0 A = 12, B = -20
I = [12x - 20 e(3 x + 5 x) ]0 /4
= 3 - 20 [ e 8 2 - e 5 ] = 3 - 20 e 25/2 + 20 e 5
= 3 - 50 e 2 + 20 e 5
Answer: (1)