Integral Calculus Question 27

Question: $ \int_{{}}^{{}}{\frac{x^{2}+x-1}{x^{2}+x-6}\ dx=} $

[AISSE 1988]

Options:

A) $x+\log \left|(x+3)\right| +\log \left| (x-2)\right|+C$

B) $x-\log \left|(x+3)\right|+\log \left| (x-2)\right|+C$

C) $x-\log \left|(x+3)\right|-\log \left| (x-2)\right|+C$

D) None of these

Show Answer

Answer:

Correct Answer: B

Solution:

$ \int_{{}}^{{}}{\frac{x^{2}+x-1}{x^{2}+x-6},dx}=\int_{{}}^{{}}{[ 1+\frac{5}{x^{2}+x-6} ]},dx $ $ =\int_{{}}^{{}}{[ 1+\frac{5}{(x+3)(x-2)} ]},dx $ $ =\int_{{}}^{{}}{dx}+\int_{{}}^{{}}{\frac{dx}{x-2}}-\int_{{}}^{{}}{\frac{dx}{x+3}} $ $ =x+\log (x-2)-\log (x+3)+c $ .