**TI92**mainProgram: 02\08\1996 05:36:54 AMRcross¥Z©() Prgm Local l,s,g,v,eqm,conm,ansm,x,y ClrIO Input "Enter light source [x, y, z]",l Input "Enter shadow",s Input "Enter viewer",v Input "Enter apparent location on the ground",g [[dotP(l-s,l-s),dotP(g-v,l-s)][dotP(l-s,g-v),dotP(g-v,g-v)]]eqm [[dotP(g-s,l-s)][dotP(g-s,g-v)]]conm simult(eqm,conm)ansm ansm[1,1]x ansm[2,1]y Disp "Estimated point of intersection" Disp .5*x*l+.5*(1-x)*s+.5*y*v+.5*(1-y)*g EndPrgmäåÜ,Š