Question

In reperul cartezian (O,i,j) se dau punctele A(-2,-2) , B(0,1) , C(-1,2) . Sa se determine coordonatele punctului D in cazurile: a) AB(cu vector deasupra)= CD(cu vector deasupra) b) AC(cu vector deasupra)=3BD(cu vector deasupra) VA ROG AJUTATI-MA!!!!! E URGENT!!!!

Answer 1

vectorial in i,j si D(x,y)
a)
AB=2i+3j
CD=(x+1)i+(y-2)j
AB=CD ⇒ x+1=2, x=1, y-2=3, y=5 ⇒ D(1,5)
b)
AC=i+4j
3BD=3[xi+(y-1)j]=3xi+(3y-3)j]
AC=3BD ⇒ 3x=1, x=1/3, 3y-3=4, y=7/3, ⇒ D(1/3 , 7/3)