LogPlot != Plot[Log]

*To*: mathgroup at smc.vnet.net*Subject*: [mg24266] LogPlot != Plot[Log]*From*: "Gy. Csanady" <csanady at gsf.de>*Date*: Wed, 5 Jul 2000 23:10:47 -0400 (EDT)*Organization*: gsf*References*: <200006020649.CAA05402@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Dear Steve Christensen, I should like to post the following question to the Mathgroup. I am relatively new with Mathematica and I encountered a problem.. Dear MathGroup, I should like to demonstrate some transformation rules graphically using Mathematica extended capabilities. However, the simplest example failed: Let assume a simple exponential function with real parameters: C1[t_] := C0*Exp[-kel*t] param = {C0 -> 100, kel -> 1} we can plot the function easily: g1 = Plot[C1[t] /. param, {t, 0, 2}, PlotRange -> {{0, 2}, {10, 100}}] We can also make a half- logarithmic plot: g2 = Plot[Log[E, C1[t]] /. param, {t, 0, 2}, PlotStyle -> {RGBColor[0, 0, 1], Dashing[{0.05, 0.05}]}, PlotRange -> {{0, 2}, {Log[10], Log[100]}}] In addition we can convert the y-axis to a logarithmic one: g3 = Show[g2, Ticks -> Join[{FullOptions[g2, Ticks][[1]], FullOptions[g2, Ticks][[2]] /. {x_, y_Real, len_, style_} :> {x, Exp[y], len, style}}]] We can obtain a half-logarithmic plot by using the LogPlot function: << Graphics`Graphics` g4 = LogPlot[C1[t] /. param, {t, 0, 2}, PlotRange -> {{0, 2}, {10, 100}}] Now I would expect that plot g4 and g3 become identic: Show[{g3, g4}, PlotRange -> All] But it is not the case. I am sure that there is something wrong. Any help would be appreciated. With best regards Gy. Csanady