Question

ПОМОГИТЕ ПОЖАЛУЙСТА!!!!

Answer 1

((a+b),c)=(a,c)+(b,c)=|a|*|c|Cos(a,c)+|b|*|c|Cos(b,c)=1*2*Cos60°+2*2*Cos60°=2*(1/2)+4*(1/2)=1+2=3

((2a-3b),c)=2(a,c)-3(b,c)=2(a,c)-3(b,c)=2|a|*|c|Cos(a,c)-3|b|*|c|Cos(b,c)=
2*1*2*Cos60°-3*2*2*Cos60°=4*(1/2)-12*(1/2)=2-6=-4