# Line function doesn't work [closed]

I want to draw a vertical line like this:

a = 10^(1/0.0015);
Line[{{a, -5}, {a, -3}}]


But there is an error: • Do you really want the $x$ value to be $\approx 10^{666}$? – David G. Stork Oct 1 '15 at 17:01
• @DavidG.Stork I put my real problem down in the comment. – yangyang Oct 1 '15 at 19:44

## 1 Answer

The error message is obscure and not as helpful as it might be, but basically your problem is that you are asking Mathematica to draw a line that is so far away form the origin that its position can not be represented with machine floating-point numbers. Unfortunately Mathematica draws all graphics with machine floats -- probably for speed, so your line segment can't be drawn.

MachineNumberQ[10^(1/0.0015)]

False

• OK. I got it. But my problem is I need to BodePlot this function: Bo = TransferFunctionModel[1/(1 + [Omega]*0.0015), [Omega]]; And I also want to show one horizontal and one vertical line which indicate the -3db cutoff frequency. I tried several times and it seems that the line should also be in logarithm range. The cut off frequency is 1/0.0015 but I need to plot a vertical line in x=10^(1/0.0015). Any suggestions? – yangyang Oct 1 '15 at 19:39
• @yangyang. You should submit your revised problem as new question. – m_goldberg Oct 1 '15 at 19:44