I am new to using maxima. I am trying to take teh partial derivative of this fuction: e(x,y,ybar,m,s):=sum(ybar[l]*product(exp(-1/2*(x-m[k])^2/s[k]^2),k,1,p), l,1,M)/sum(product(exp(-1/2*(x-m[k])^2/s[k]^2),k,1,p),l,1,M)-y; w.r.t m (for example). Any suggestions? Or, am I just doing this all wrong? Jim