Răspuns:
AB=B-A=(2,3)-(1,0)=(2-1,3-0)=(1,3)
AC=C-A=(-1-1,4-0)= -2,4)
AB*AC=(1,3)*(-2,4)=1*-2+3*4=-2+12=10
____________________
CB=B-C=(2,3)-(-1,4)=
(2-(-1),3-4)=(2+1,-1)=(3,-1)
AB+CB=(1,3)+(3,-1)=(1+3,3-1)=(4,2)
lAB+CBl=√(4²+2²)=√16+4=√20=2√5
Explicație pas cu pas: