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 Apr 2 awarded Popular Question Jul 17 awarded Notable Question Jan 17 awarded Popular Question Jul 2 awarded Curious Apr 23 awarded Popular Question Mar 25 accepted logplot for negative valued function Mar 21 awarded Teacher Mar 21 answered logplot for negative valued function Mar 21 revised logplot for negative valued function deleted 345 characters in body Mar 21 awarded Informed Mar 21 revised logplot for negative valued function added 347 characters in body Mar 21 comment logplot for negative valued function Not, exactly, but I see the solution, because this does the work myTicks = N[Table[{10^-i, -10^i}, {i, -9, 1}]]; LogPlot[- f[x], {x, 0, 100}, Frame -> True, PlotRange -> {10^-9, 10}] LogPlot[-f[x]^-1, {x, 0, 100}, Frame -> True, PlotRange -> {1/10, 10^9}, FrameTicks -> {Automatic, myTicks, None, None}] Mar 21 asked logplot for negative valued function Aug 15 awarded Nice Question Jul 20 comment Integration leading to logarithms and chosing branch @Artes Thanks for the link. It might be useful also ;) Jul 20 comment Integration leading to logarithms and chosing branch This works awesome for me! Just what I was looking for. The problem is I had to evaluate in the intercal {t,0,Infinity}, but the divergence at 0 is cancelled from an additional part Log[0]. Now I can do the job with Limit[Evaluate[Integrate[(((1 + b*t)^2) t)^(-1), {t, Infinity, τ}, Assumptions -> b > 0 && τ > 1]]+Log[τ],τ->0] which yields the desired result which you can calculate by hand to be -1+Log[1/b] Now is easier, but I wanted to fix it since the function to be integrated will be more complicated later. Thanks a lot! Jul 20 accepted Integration leading to logarithms and chosing branch Jul 20 comment Integration leading to logarithms and chosing branch Thanks for all the clarifications. I was just pieced off by the point that, if I would evaluate my result say, in the interval (2,10) I would get an imaginary part, while this would make no-sense for a definite integral. I was just wondering whether I could tell Mathematica some assumption so it would choose the desired sign in my case. Nevertheless, the solution below works perfecto for me :) Jul 19 asked Integration leading to logarithms and chosing branch Jun 29 comment Ignoring Indeterminate Results Ok, sorry. Finally the problem was solved using Table instead of Array, which keeps the problematic results in the vector. An alternative is not to add the ; at the end, so the output with error is produced and can be further used. However, the problematic parts must be removed by hand, since they are not labelled by Indeterminate rather than NIntegrate[...]. However, being rare such cases they don't represent a huge problem