Question

VA ROG AM NEVOIE URGENT!!!! DAU COROANA CELUI MAI BUN RASPUNS!!!!​

Answer 1

Răspuns:

$1) A(1,1),B(-1,3),C(-3,-2),D(2,-1), O(0,0)\\OA=(xa-xo,ya-yo)=(1-0,1-0)=>OA=(1,1)\\=>OB=(-1,3),OC=(-3,-2),OD=(2,-1)\\AB=(xb-xa,yb-ya)=(-1-1,3-1)=>AB(-2,2)\\AC=(xc-xa,yc-ya)=(-3-1,-2-1)=>AC(-4,-3)\\AD=(xd-xa,yd-ya)=(2-1,-1-1)=>AD(1,-2)$

$2) A(1,5),B(-1,3),C(2,-4)\\|AB|^2=(xb-xa)^2+(yb-ya)^2=(-1-1)^2+(3-5)^2=(-2)^2+(-2)^2=4+4\\=>|AB|^2=8=>|AB|=2\sqrt{2}\\|BC|^2=(xc-xb)^2+(yc-yb)^2=(2-(-1))^2+(-4-3)^2=(2+1)^2+(-7)^2\\=9+49=58=>|BC|=\sqrt{58} \\|AC|^2=(xc-xa)^2+(yc-ya)^2=(2-1)^2+(-4-5)^2=1^2+(-9)^2\\=1+81=82=>|AC|=\sqrt{82}$