Question

дано: А(-2;4), В(3;3), C(5;-1) Найти:вектора AB; AC; |AB|; |AC| Cos<BAC

Answer 1

$bar Abar B=left{3-(-2);;3-4right}={5;;-1}\bar Abar C=left{5-(-2);;-1-4right}={7;;-5}\left|ABright|=sqrt{5^2+(-1)^2}=sqrt{25+1}=sqrt{26}\left|ACright|=sqrt{7^2+(-5)^2}=sqrt{49+25}=sqrt{74}\cosangle BAC=frac{(bar{AB},bar{AC})}{|AB||AC|}=frac{5cdot7+(-1)cdot(-5)}{sqrt{26}cdotsqrt{74}}=frac{35+5}{sqrt{1924}}=frac{40}{sqrt{1924}}$

Answer 2

че за ху1ня?