# `int_1^oo lnx/x dx` Determine whether the integral diverges or converges. Evaluate the integral if it converges.

`int_1^infty (ln x)/x dx=`

Substitute `u=lnx` `=>` `du=1/x dx,` `u_l=ln 1=0,` `u_u=ln infty=infty` (`u_l` and `u_u` denote lower and upper bound respectively).

`int_0^infty u du=u^2/2|_0^infty=lim_(u to infty) u^2/2-0^2/2=infty-0=infty`

As we can see the integral does not converge.

The image below shows graph of the function and area under it representing the value of the integral. Looking at the image we can see that the graph approaches the x-axis (function converges to zero). However, this convergence is "relatively slow" and gives us infinite area under the graph.

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