Can we create a trend line with a custom equation, for example y = a*x^b + c?

(3 arguments to be estimated: *a*, *b* and *c*, which are real numbers).

Thank you.

Can we create a trend line with a custom equation, for example y = a*x^b + c?

(3 arguments to be estimated: *a*, *b* and *c*, which are real numbers).

Thank you.

Thanks, but that doesn’t seem to be what I’m looking for. The custom equation I mentioned above is a power function (with 2 terms) and not a polynomial one (the CorelPolyGUI extension is for polynomial function only, isn’t it?).

Hi @Nesbit, if you insist having b as a real number you are right. Polynomial function have b as integer. Other option: insert an extra Y-column in your xy-chart with your equation.

Hi @horst. Sorry for the late reply.

I think you misunderstood my question. In the equation, the three coefficients *a*, *b* and *c* are the arguments to be estimated (i.e. *a*, *b* and *c* are unknown) so that the trend line fit the data.

For example, for a set of data A, we find *a* = 0.5, *b* = 0.2, *c* = 1.2. For another set of data B, we find *a* = 0.7, *b* = 0.5, *c* = 1.5.

Hope that’s clear enough.

Have a nice day !