I have graphs of (X,Y) cordinates (5, 0.19), (10, 0.38) & (20,0.78) respectively. In my VI labeled AA, the horizontal cursor tracks perfectly from 5 to 10 and not so well from 10 to 20. This is just as one would expect, since the slope from 10 to 20 has changed slightly. In vi labeled AB, I have made the code calculate the new slope and would expect correct tracking from 10 to 20. I was only able to achieve tracking by including a 0.4848 offset and even then it is not exact. A 0.38 offset might be understandable, but at present I cannot explain the error. I wish to understand this so that I can increase the complexity of my graphs and then experiment with "in range and co-erce". Any guidance would be much appreciated.
graph 3 points AA.vi
graph 3 points AB.vi