# integration check 2

• Nov 10th 2008, 03:37 AM
jvignacio
integration check 2
$
\int_{-2}^{-1} \frac{1}{3-4x}
$

$
= (\frac{-1}{4}log(3-4(-1))) - (\frac{-1}{4}log(3-4(-2)))
$

$
= 0.049073661
$

correct? thank you
• Nov 10th 2008, 03:39 AM
mr fantastic
Quote:

Originally Posted by jvignacio
$
\int_{-2}^{-1} \frac{1}{3-4x}
$

$
= (\frac{-1}{4}log(3-4(-1))) - (\frac{-1}{4}log(3-4(-2)))
$

$
= 0.049073661
$

correct? thank you

No. The final numerical answer is wrong.
• Nov 10th 2008, 04:00 AM
jvignacio
Quote:

Originally Posted by mr fantastic
No. The final numerical answer is wrong.

the decimal places? is the substitution correct? where i enter -1 and -2 in for the x's?
• Nov 10th 2008, 04:02 AM
mr fantastic
Quote:

Originally Posted by jvignacio
the decimal places? is the substitution correct? where i enter -1 and -2 in for the x's?

Quote:

Originally Posted by jvignacio
$
\int_{-2}^{-1} \frac{1}{3-4x}
$

$
= (\frac{-1}{4}log(3-4(-1))) - (\frac{-1}{4}log(3-4(-2)))
$
Mr F says: Correct.

= 0.049073661 Mr F says: Wrong.

correct? thank you

..
• Nov 10th 2008, 04:15 AM
jvignacio
Quote:

Originally Posted by mr fantastic
..

wierd. my calculator is giving me that answer.
• Nov 10th 2008, 04:21 AM
mr fantastic
Quote:

Originally Posted by jvignacio
wierd. my calculator is giving me that answer.

Then you're not entering the expression into your calculator correctly. Like the old saying says: Garbage in, garbage out.
• Nov 10th 2008, 04:28 AM
jvignacio
Quote:

Originally Posted by mr fantastic
Then you're not entering the expression into your calculator correctly. Like the old saying says: Garbage in, garbage out.

hrmmm could be. ive tryed a few things and i keep getting the same answer.. ill keep trying
• Nov 10th 2008, 04:50 AM
qorilla
The 'log' on your calculator means logarithm to base 10.
Use the 'ln' button for e-based logarithm.
• Nov 10th 2008, 06:48 AM
jvignacio
Quote:

Originally Posted by qorilla
The 'log' on your calculator means logarithm to base 10.
Use the 'ln' button for e-based logarithm.

much appreciated! thank you