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Nov1-04, 01:21 PM
P: 94
I'll use this thread instead of creating a new one. I'm working on creating emphiric functions given various data-sets.

Linear functions and as shown above exponential functions are fine.
Now I'm working with functions that are similar to exponential functions, but using log.
I want a function of the form: [itex]f(x) = c * x^r[/itex]

The data set:
[itex](\log{x_0}, \log{y_0}), (\log{x_1}, \log{y_1}).[/itex]

There might obviously be more points. From these points, we try to draw out a straight line as possible on a graph. Then find the graphs slope(?) graphically with a ruler. ie
[itex]\frac{\Delta x}{\Delta y} = r[/itex]

Now we have:
[itex]c * x_0^r = y_0 \rightarrow c = \frac{y_0}{x_0^r}[/itex]

I've tried this out with various data, but my function is always very inaccurate. It's 100% for the point I use to find 'c', but for any other point the result might be as much as 50% off. I know it's an emphiric function, but I would expect I would be able to get it more accurate.

Is this normal?