On a semilogy plot, how to plot a line connecting two given points A&B and perform linear interpolation

As the question says, I would like to connect two points on a semilogy plot and perform linear interpolation. For example, given two points A(0,1) and B(10,1), draw out the straight line and find y value for x=5.

Answer 1

[Walter Roberson]

Lx = [A(1),B(1)]; Ly = [A(2), B(2)];
hold on
plot(Lx, Ly, 'c-');    %the connecting line

probe_x = 5;
probed_y = interp1(Lx, Ly, probe_x);
plot(probe_x, probe_y, 'r*');

hold off

This will draw a straight line on the semilogy plot. Which, when you think about it, is likely to be the wrong thing to do, because straight lines in log plots imply constant exponential growth.