Question

решите пжжжжжжжж 2 и 5​

Answer 1

2) Координаты a-2b = {2-0*2; -1-1*2; 3-(-4)*2}= {2;-3;11}

Длина: |a-2b|=√(4+9+121)=√134

5) cosα= (ab)/(|a|*|b|) = (x1x2+y1y2+z1z2)/(√(x1²+y1²+z1²)(x2²+y2²+z2²)= (3*2+1*3-2*0)/(√14√13)=9/√182 => α=arccos(9/√182)