Hi,
It works, thanks!
but it doesn't return any results.
> (%i9) display2d:false;
> (%o9) false
> (%i10) declare(sum,linear);
> (%o10) done
> (%i11) eq:2*sum((X[i]*(((c*X[i]+d)^2*t)/2-(a*X[i]+b)*t+R[i]))/(c*X[i]+d)^2,i,1,M)=0;
> (%o11) 2*'sum(X[i]*((c*X[i]+d)^2*t/2-(a*X[i]+b)*t+R[i])/(c*X[i]+d)^2,i,1,M) = 0
> (%i12) solve(eq,a);
> (%o12) [a =
> -((2*b*'sum(X[i]/(c*X[i]+d)^2,i,1,M)-'sum(X[i],i,1,M))*t-2*'sum(R[i]*X[i]/(c*X[i]+d)^2,i,1,M))/
> (2*('sum(X[i]^2/(c*X[i]+d)^2,i,1,M))*t)]
>
The next thing I wanted is to do is:
solve([diff(L, a), diff(L,b)], [a,b]);
but it doesn't return any results.
I managed to work around it by doing:
solve([solve(diff(L, a), a)[1], solve(diff(L,b),b)[1]], [a,b]);
but probably I am doing something wrong again...
Regards,
Grzegorz
And how can I plug these values back into the original equation L (or
some other equation that contains a and b)?