syms ax ay bx by cx cy real
av = [ax ay 0].';
bv = [bx by 0].';
cv = [cx cy 0].';
ab = dot(av,bv);
bc = dot(bv,cv);
ac = dot(av,cv);
display(ab);
display(bc);
display(ac);
axn=input('ax= ');
ayn=input('ay= ');
bxn=input('bx= ');
byn=input('by= ');
cxn=input('cx= ');
cyn=input('cy= ');
abn=subs(ab,[ax ay bx by],[axn ayn bxn byn]);
bcn=subs(bc,[bx by cx cy],[bxn byn cxn cyn]);
acn=subs(ac,[ax ay cx cy],[axn ayn cxn cyn]);
abn=eval(abn);
bcn=eval(bcn);
acn=eval(acn);
display(abn)
display(bcn)
display(acn)