In[]:=
X=1.9066Y=-0.09122Z=-0.43421R=1.95756
Out[]=
1.9066
Out[]=
-0.09122
Out[]=
-0.43421
Out[]=
1.95756
In[]:=
Solve[{X*(((Cos[c])*(Cos[b]))-(Cos[b])*(Sin[a])*(Sin[c]))+Y*((Cos[c])*(Sin[a])+(Cos[a])*(Cos[b])*(Sin[c]))+Z*(Sin[c]*(Sin[b]))0,X*((-Sin[c])*(Cos[a])-(Cos[b])*(Sin[a])*(Cos[c]))+Y*((-Sin[c])*(Sin[a])+(Cos[b])*(Cos[a])*(Cos[c]))+Z*(Cos[c]Sin[b])0,(X*Sin[b]*Sin[a]-Y*Sin[b]*Cos[a]+Z*Cos[b])1.95756},{a,b,c}]