[cga@ux10 ~]$ math Mathematica 5.0 for Linux Copyright 1988-2003 Wolfram Research, Inc. -- Motif graphics initialized -- In[1]:= Rz[angle_]={{Cos[angle],-Sin[angle],0},{Sin[angle],Cos[angle],0},{0,0,1}} Out[1]= {{Cos[angle], -Sin[angle], 0}, {Sin[angle], Cos[angle], 0}, {0, 0, 1}} In[2]:= link1 = {l1,0,0} Out[2]= {l1, 0, 0} In[3]:= link2 = {l2,0,0} Out[3]= {l2, 0, 0} In[4]:= ans = Rz[a1].(link1 + Rz[a2].link2) Out[4]= {Cos[a1] (l1 + l2 Cos[a2]) - l2 Sin[a1] Sin[a2], > (l1 + l2 Cos[a2]) Sin[a1] + l2 Cos[a1] Sin[a2], 0} In[5]:= ans = Simplify[ ans ] Out[5]= {l1 Cos[a1] + l2 Cos[a1 + a2], l1 Sin[a1] + l2 Sin[a1 + a2], 0} In[6]:= CForm[ans] Out[6]//CForm= List(l1*Cos(a1) + l2*Cos(a1 + a2),l1*Sin(a1) + l2*Sin(a1 + a2), 0) In[7]:= Quit