$Assumptions={ Element[d, Integers] && d>=1 && d<=2 \ && Element[u1, Reals] \ && Element[u2, Reals] \ && Element[Xi1, Reals] \ && Element[Xi2, Reals] \ && Element[y, Reals] && Element[w, Reals] }; (*************************************************************) (*************************************************************) P[Xi1_, Xi2_, Eta1_, Eta2_] := \ C2010*Xi1*Xi1*Eta1 + C2001*Xi1*Xi1*Eta2 \ + C0210*Xi2*Xi2*Eta1 + C0201*Xi2*Xi2*Eta2 \ + Xi1*(M11*Xi1 + M12*Xi2 + M13*Eta1 + M14*Eta2)/2 \ + Xi2*(M12*Xi1 + M22*Xi2 + M23*Eta1 + M24*Eta2)/2 \ + Eta1*(M13*Xi1 + M23*Xi2 + M33*Eta1 + M34*Eta2)/2 \ + Eta2*(M14*Xi1 + M24*Xi2 + M34*Eta1 + M44*Eta2)/2 \ + V1*Xi1 + V2*Xi2 + V3*Eta1 + V4*Eta2 \ + S; (*************************************************************) (*************************************************************) Xi1[d_, y1_, y2_, y3_]:= If[ d==1, 1, y2 ]; Xi2[d_, y1_, y2_, y3_]:= If[ d==1, y1, y2*y3 ]; Eta1[d_, y1_, y2_, y3_]:= If[ d==1, y2, 1 ]; Eta2[d_, y1_, y2_, y3_]:= If[ d==1, y2*y3, y1 ]; (*************************************************************) (* script P functions ***************************************) (*************************************************************) MySeries[1, w_, y1_, y2_, y3_] = Series[ P[ w*Xi1[1, y1, y2, y3], w*Xi2[1, y1, y2, y3], w*Eta1[1, y1, y2, y3], w*Eta2[1, y1, y2, y3] ], {w, 0, 10}]; MySeries[2, w_, y1_, y2_, y3_] = Series[ P[ w*Xi1[2, y1, y2, y3], w*Xi2[2, y1, y2, y3], w*Eta1[2, y1, y2, y3], w*Eta2[2, y1, y2, y3] ], {w, 0, 10}];