Regression of a trigonometric function or of an exponential function

Forum|Forum|15 years ago
March 16, 2011
1 reply
7028 views

Hi,

is it possible to do a regression as simple as in a graphing calculator?

There I have got a statistic menu where i can write down my x and y values. Then I hit the [Reg]ression button and the [sin]us button. Done.

I tried to solve my problem in MathCad with 2 vectors and the sinfit function, but it does not work 😕

There is the same problem with an exponential function...

There I used expfit, where it said the "guessing"-vector is optional, so I left it out. -> No solution...

Can u help me??

Thank You.

Other

Best answer by RichardJ

Mathcad's sinfit function is essentially useless. There is no multiplier for x, and that multiplier changes the frequency of the sin wave. Whoever originally implemented this function, with no ability to vary the frequency, must have been mentally deficient!

Here's a generic approach to fitting. You can use this to fit any function, not just the few built-in ones.