1.

` int_(-1)^(1) (dx) / (x^(2)+2x+5)` is equal toA. `pi/2`B. `pi/4`C. `pi/8`D. `pi/3`

Answer» Correct Answer - C
` int _(-1)^(1) 1/(x^(2)+2x+5)dx= int_(-1)^(1)1/((x^(2)+2x+1)+4)dx`
` = int _(-1)^(1) 1/((x+1)^(2)+2^(2))dx=1/2[ tan^(-1).(x+1)/2]_(-1)^(1)`
` = 1/2 [ tan^(-1)(2/2)-tan^(-1)(0/2)]`
` = 1/2 [ tan^(-1)1] = 1/2 xx pi/4 = pi/8`


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