Задача 45164 ...

sova

2020-03-20 12:46:38

vector{TA}=(-1-1;0-(-1);1-3)=(-2;1;-2)
vector{TC}=(1-1;3-(-1);3-3)=(0;4;0)

vector{TA}*vector{TC}=-2*0+1*4+(-2)*0

|vector{TA}|=sqrt((-2)^2+1^2+(-2)^2)=3

|vector{TC}|=sqrt(0^2+4^2+0^2)=4


сos ∠ T=[m]\frac{\vec{TA}\cdot\vec{TC}}{|\vec{TA}|\cdot|\vec{TC}|}=\frac{1}{3}[/m]