Question

已知向量a=(1,-1),b=(2,-4),求与2a+b垂直地单位e

Answer 1

垂直单位向量e=(x,y)x^2+y^2=1 (1)(2a+b).e=0(4,-6).(x,y)=04x-6y=0x= 3y/2 (2)sub (2) into (1)9y^2/4 +y^2 =1y^2=4/13y = 2√13/13 or -2√13/13e=(3√13/13 ,2...