S sy211006 New member Joined Feb 12, 2009 Messages 5 Feb 15, 2009 #1 i keep going in circles could someone please help me prob integral ln(2x+1) dx i use u=ln dx and dv=2x+1 when i integrate it seems that i just keep going in circles
i keep going in circles could someone please help me prob integral ln(2x+1) dx i use u=ln dx and dv=2x+1 when i integrate it seems that i just keep going in circles
G galactus Super Moderator Staff member Joined Sep 28, 2005 Messages 7,203 Feb 15, 2009 #2 \(\displaystyle \int ln(2x+1)dx\) You can not use the choices you have. Let \(\displaystyle u=ln(2x+1), \;\ dv=dx, \;\ du=\frac{2}{2x+1}dx, \;\ v=x\) \(\displaystyle xln(2x+1)-2\int\frac{x}{2x+1}dx\) Now, can you finish by integrating the last one?. Substitution would be easier, unless you have to use parts.
\(\displaystyle \int ln(2x+1)dx\) You can not use the choices you have. Let \(\displaystyle u=ln(2x+1), \;\ dv=dx, \;\ du=\frac{2}{2x+1}dx, \;\ v=x\) \(\displaystyle xln(2x+1)-2\int\frac{x}{2x+1}dx\) Now, can you finish by integrating the last one?. Substitution would be easier, unless you have to use parts.
S sy211006 New member Joined Feb 12, 2009 Messages 5 Feb 15, 2009 #3 thank you now i will try the rest on my own i have to use intergration by parts might have more questions later wish me luck
thank you now i will try the rest on my own i have to use intergration by parts might have more questions later wish me luck
S sy211006 New member Joined Feb 12, 2009 Messages 5 Feb 15, 2009 #4 ok i am worse than i thought... please show me the next step
D Deleted member 4993 Guest Feb 15, 2009 #5 galactus said: \(\displaystyle xln(2x+1)-2\int\frac{x}{2x+1}dx\) \(\displaystyle =\, xln(2x+1)-\int\frac{2x+1 \, - \, 1}{2x+1}dx\) DUPLICATE POST viewtopic.php?f=3&t=32795&p=127514#p127514 Click to expand...
galactus said: \(\displaystyle xln(2x+1)-2\int\frac{x}{2x+1}dx\) \(\displaystyle =\, xln(2x+1)-\int\frac{2x+1 \, - \, 1}{2x+1}dx\) DUPLICATE POST viewtopic.php?f=3&t=32795&p=127514#p127514 Click to expand...