Here is the integral: sqrt[x^2 - 9]/x^2.

I know the answer (ln (x + sqrt[x^2+9]) - (sqrt[x^2 - 9]/x))

How does this answer come about? I have tried using the trig functions and I am getting no where close to the answer.

Cheers!

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- Jun 19th 2009, 08:22 PMjackm7evaluate the integral
Here is the integral: sqrt[x^2 - 9]/x^2.

I know the answer (ln (x + sqrt[x^2+9]) - (sqrt[x^2 - 9]/x))

How does this answer come about? I have tried using the trig functions and I am getting no where close to the answer.

Cheers! - Jun 19th 2009, 08:27 PMmalaygoel
have you tried$\displaystyle x=3sec\theta$