Avoid crooked line in $\log(\frac{a+1}{c+1})$ contour plot?

[kjyong (Jayong Kim)]

I plotted contour plot of this formula by Wolfram Alpha

\log(\frac{a+1}{c+1}), 0 < a < 1000, 0 < c < 1000

In the above figure, there is a crooked line in the bottom part. If I plot this, there is no crooked line.

\log(\frac{a}{c}), 0 < a < 1000, 0 < c < 1000

Why there is crooked line in the first case?

[mariuszi28cg (Mariusz Iwaniuk)]

Hi

Wolfram Alfa uses a standard options to display ContourPlots. Maybe it’s related to performance and display time

In Mathematica we have to controls on all options.

ContourPlot[Log[(a + 1)/(c + 1)], {a, 0, 1000}, {c, 0, 1000},  
FrameLabel -> Automatic](*Automatic option like WolframAlfa*)

PlotPoint option is to get smoother contours.

ContourPlot[Log[(a + 1)/(c + 1)], {a, 0, 1000}, {c, 0, 1000},  
FrameLabel -> Automatic, PlotPoints -> 100](*And here we need more CPU time*)

Regards,
Mariusz.

[kjyong (Jayong Kim)]

Oh I got it. Thanks for the reply!