# Finding the mathematical function is plotted by using the bodeplot command

I've the following code:

BodePlot[{1/(((5.601443110900379*^-8)*(5.601443110900379*^-8)*(1.\
6672176431702952*^-7)*(56000)*(56000 +
56000)*((56000*56000)/(56000 + 56000)))*(2*Pi*f*
I)^3 + ((5.601443110900379*^-8)*(5.601443110900379*^-8)*(\
56000)*(56000 +
56000) + \
(5.601443110900379*^-8)*(1.6672176431702952*^-7)*(56000)*(56000 +
56000))*(2*Pi*f*
I)^2 + ((5.601443110900379*^-8)*(56000) + \
(5.601443110900379*^-8)*(56000 + 56000 + 56000))*(2*Pi*f*I) +
1)}, {f, 0, 100},
ScalingFunctions -> {{"Linear", "dB"}, {"Linear", "Degree"}},
ImageSize -> Large]


This code gives two plots, the amplitude and the phase.

How can I find the function that is plotted as the phase? I mean can I aks Mathematica what kind of function (exp, arctan, arccos or arcsin etc.) it has plotted to plot the phase?

• The phase should be Arg. So try your formula with a simple Plot and wrap Arg around it. Since this will give values from -Pi to Pi, you need to process this. You could use toDegree[arg_] := Mod[arg, 2 Pi]/(2 Pi)*360 or you set ScalingFunctions` appropriately. – halirutan Jul 2 '18 at 20:27