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1/lnx dx take the integral pls

2007-01-24 19:26:37 · 7 answers · asked by akliniozgurbirak 1 in Science & Mathematics Mathematics

I am not saying take the derivative, I can not draw here integral's symbol. 1/lnx dx INTEGRAL

2007-01-24 19:35:39 · update #1

SO, if I could not express this with normal functions, what am I suppose to do?
erf ? si?

2007-01-24 22:02:00 · update #2

7 answers

Summation of [(lnx) ^ n] / [n(n!)] + C, where n = 1 to infinity.
You cannot express this integral into a simpler one.

2007-01-24 19:56:16 · answer #1 · answered by Joe Mkt 3 · 1 0

No closed form solution exists, but one can get a series solution as follows: Change variables by u = ln x. Then exp^u = x, so exp^u du = dx. So thie new integral in terms of u is of (exp^u)/u. Write exp^u as a series, divid each term by u and integrate. You get

ln u + u + (u^2)/[2*2!] + ... +( u^n)/[n*n!] +....

Replace u with ln x to get the final answer.

2007-01-28 16:32:33 · answer #2 · answered by berkeleychocolate 5 · 0 0

I know,the integration is below.Read properly.
Integrate 1/lnx dx= ln|x| +c

2007-01-24 19:34:06 · answer #3 · answered by A 150 Days Of Flood 4 · 0 1

You CAN NOT express this integral as a combination of so called elementary functions as e^x ,lnx.sinx,cosx,polynomials etc)

2007-01-24 21:59:39 · answer #4 · answered by santmann2002 7 · 0 0

?sqrt(a million+lnx) / xlnx dx = ?sqrt(a million+u) / u du, the place u = lnx = ?v / (v^2 - a million) 2vdv, the place v = sqrt(a million+u), u = v^2 - a million du = 2vdv = ?2 + (a million/(v-a million) - a million/(v+a million)) dv = 2v + ln|v-a million| - ln|v+a million| = 2sqrt(a million+lnx) + ln|lnx| - ln|2+lnx| + c

2016-11-01 05:41:06 · answer #5 · answered by ? 4 · 0 0

Impossible to express with usual functions. Don't try!

2007-01-24 19:30:25 · answer #6 · answered by gianlino 7 · 1 1

I have not the answer but have found a site that could be interesting

2007-01-25 01:20:38 · answer #7 · answered by maussy 7 · 0 0

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