How do I solve a equation using lsqnonlin, but have solutions bound by another equation?

Hi,

I'm trying to use lsqnonlin to find parameters of an equation:

y = a1.*x^2 + a2.*x + a3

where a1, a2 and a3 are parameters.

I also want to implement a constraint equation:

a1 + a2 + a3 = 1

How do I go about implementing this constraint equation into lsqnonlin?

Thanks

Answer 1

[Walter Roberson]

Pass in one fewer value and calculate the third value as 1 - sum() of the others.