fdparam1[n_,x1_]:=n/(n+x1);
fdmax=0.97; fdmin=0.7;
fdloadfactorout[n_,x1_]:=fdmax-(fdmax-fdmin)*fdparam1[n,x1]
inmax=256; ix1max=64;
Plot3D[fdparam1[n,x1],{n,0,inmax},{x1,1,ix1max}]
Plot3D[fdloadfactorout[n,x1],{n,0,inmax},{x1,1,ix1max}]