Help with Calc!!





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Discus: SAT/ACT Tests and Test Preparation: May 2004 Archive: Help with Calc!!
By Cantwait4colleg (Cantwait4colleg) on Monday, May 10, 2004 - 10:40 pm: Edit

Stupid question...

Integral of (1/x)dx from 0 to 1...

By Miseryxsignals (Miseryxsignals) on Monday, May 10, 2004 - 10:52 pm: Edit

integral of 1/x = lnx.

soo... ln(1) - ln(0). And you cant do the ln(0), Sorry.

By Athlonmj (Athlonmj) on Monday, May 10, 2004 - 10:54 pm: Edit

Yes you can, it's an improper integral so substitute a for 0 and take the limit as it approaches 0.

By Efilsiertaeht (Efilsiertaeht) on Monday, May 10, 2004 - 11:05 pm: Edit

approaches 0, not infinity.

By Sandwraith (Sandwraith) on Monday, May 10, 2004 - 11:05 pm: Edit

either way the point is that the value of the integral is not a finite answer

By Mike105 (Mike105) on Monday, May 10, 2004 - 11:07 pm: Edit

ò0 1(1/x)dx = ¥

By Miseryxsignals (Miseryxsignals) on Monday, May 10, 2004 - 11:13 pm: Edit

haha oops. Shows what a year w/o math can do to you. SOrry about that, thanks for catching my mistake! :)

By Ubercollegeman (Ubercollegeman) on Monday, May 10, 2004 - 11:40 pm: Edit

That is an improper integral. If you want the full way to do it..

lim a->0+ ln(1) - ln(a) =

lim a->0+ 0 - lna = -(-infty) = infty.
^not good mathematical notation, but whatever!


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