chebyshev sine approx

[vishnu36]

I am looking for coefficients (floating point) for 5th degree chebyshev sine/cosine function. Could any body help me with this. Purpose is to implement custom trig function in a microcontroller

 

[G4BCH]

A serach for 'coefficients (floating point) for 5th degree chebyshev sine/cosine function' found this as first hit.

Chebyshev Approximation and How It Can Help You Save Money, Win Friends, and Influence People - Jason Sachs

Well... maybe that's a stretch. I don't think I can recommend anything to help you win friends. Not my forte. But I am going to try to convince you why you should know about Chebyshev...

www.embeddedrelated.com

I think the values you need are about half way down the page

 

[vishnu36]

I was looking for coeff in the range -pi to +pi, which is not listed in this page

 

[std_match]

Also look at a CORDIC implementation. It is probably better than polynomial implementations in small microcontrollers, especially if multiplication (with the required precision) can't be done in hardware.