A(xA;yA)
B(xB;yB)
|AB|= ✓(xB-xA)²+(yB-yA)²
lungimea unui vector
(sau modulul unui vector)
a)|AB|=✓(4-1)²+(7-3)² = ✓3²+4²=✓9+16=
=✓25 =5
b)|AB|=✓(-1-2)²+(4-8)²=✓(-3)²+(-4)²=✓9+16=5
c)|AB|=✓(3-1)²+(4-0)²=✓2²+4²=✓4+16=✓20=
=✓2•2•5 = 2✓5
d)|AB|=✓(2-2)²+(5-1)²=✓0²+4²=✓4²=4
e)|AB|=✓(-4-2)²+(8-0)²=✓(-6)²+8²=✓36+64=
=✓100=10
f)|AB|=✓(4-5)²+(2-(-1))²=✓1²+(2+1)²=✓1+3²=
=✓1+9=✓10
AB mereu cu săgeata deasupra!!!