Question

Определите угол между векторами а(4;3) в(1;7)

Answer 1

cos A = (a * b)/( IaI * IbI)
a*b= 4*1+3*7=4+21=25
IaI=sqrt(16+9)=5
IbI=sqrt(1+49)=sqrt(50)=sqrt(25*2)= 5sqrt(2)
cos A = 25/(5*5sqrt(2)) = 25/25sqrt(2)=1/sqrt(2) = sqrt(2)/2
A = 45
Ответ:45