Evaluate a fraction in a definite integral?

[lilypeach]

I don't understand how to evaluate a fraction in a definite integral, could anyone please explain this problem to me?

int. between 3 (lower integral) and 4 (upper integral) of 3x^2+2/x^2

I thought of using the substitution law, and got as far as 1/6 u * du/x ...I don't quite know how to proceed...

Your help is greatly appreciated!

 

[Mark44]

I don't understand how to evaluate a fraction in a definite integral, could anyone please explain this problem to me?

int. between 3 (lower integral) and 4 (upper integral) of 3x^2+2/x^2

I thought of using the substitution law, and got as far as 1/6 u * du/x ...I don't quite know how to proceed...

Your help is greatly appreciated!

The most obvious approach is to divide 3x² + 2 by x². I'm assuming that you meant (3x² + 2)/x². A literal interpretation of what you wrote would be 3x² + (2/x²). You don't need to use substitution.

BTW, there is no "substitution law." It's just a technique for evaluating integrals.

 

[lilypeach]

thank you!