another definite integral

**foodmmm** · April 14th 2009, 06:53 AM

$ \int_{1}^2 (6e^{3x}-1/x)\, dx $

**Calculus26** · April 14th 2009, 07:00 AM

= 2*e^3x-ln(x) = 2e^6-ln(2)-2*e^3

**mr fantastic** · April 14th 2009, 07:02 AM

Originally Posted by foodmmm

$ \int_{1}^2 (6e^{3x}-1/x)\, dx $

You're integrating standard forms. Read this carefully (most of the formulae should be in your class notes or textbook): Table of Integrals

**foodmmm** · April 14th 2009, 07:11 AM

what did you get as the final answer?

2e^6 - ln(2) - 2e^3 ?

**mr fantastic** · April 14th 2009, 07:13 AM

Originally Posted by foodmmm

what did you get as the final answer?

2e^6 - ln(2) - 2e^3 ?

Yes.

**foodmmm** · April 14th 2009, 07:17 AM

there is no + c on the end?

**mr fantastic** · April 14th 2009, 07:21 AM

Originally Posted by foodmmm

there is no + c on the end?

It's a definite integral. There's only a '+ c on the end' when it's an indefininte integral.

**Calculus26** · April 14th 2009, 07:22 AM

If you add c (F(b)+c)-(F(a)+c) =F(b) -F(a) so c is omitted from definite integrals

**foodmmm** · April 14th 2009, 07:22 AM

thank you

Thread: another definite integral