The integral 1/43/4 (2 -1 1 - x1 + x ) dx is equal to
- -1/2
- -1/4
- 1/4
- 1/2
Answer
(2) -1/4
Solution
Let = -1 1 - x1 + x; then = 1 + x1 - x, since > 0.
Using 2 = 1 - 2 1 + 2 , the integrand becomes
2 = 1 - 1 + x1 - x1 + 1 + x1 - x = (1 - x) - (1 + x)(1 - x) + (1 + x) = -x
I = 1/43/4 (-x) dx = - [ x22 ]1/43/4
= - 12 ( 916 - 116 ) = - 14
Answer: (2)