How to create a line from a curve in a log scale x-axis

Hello, I'm doing a code that needs to find the intersection of 2 lines. The first line is with y constant (slope 0) and the second is created from the inglection point following the curbe as shown in the figure, with the 'o' points the inflection points already calculated. The problem is that the curbe is ploted in a x-scale and I don't know to create those curves and plot them like in the figure. Does anyone know how it could be made? thanks

Answer 1

[Simon Allosserie]

If your question is how to plot a log scale, please use

set(gca, 'XScale', 'log') %make X axis logarithmic

[Lluis Montell de Jesus]

No, I mean when I plot the cruve in a log scale I have the shape of this graph. I want to calculate the black line that is tangent of the cruve in the log scale considering that of course I have the points of the blue curve and the point that I want the line passes.