a) |$\underset{AB}{\rightarrow}$ + $\underset{BC}{\rightarrow}$| = a
b) |$\underset{AB}{\rightarrow}$ - $\underset{AC}{\rightarrow}$| = a
c) |$\underset{AB}{\rightarrow}$ + $\underset{AC}{\rightarrow}$| = a$\sqrt{a}$
Bài 39 : Cho tam giác đều ABC cạnh a. Tính:
a) |$\underset{AB}{\rightarrow}$ + $\underset{bc}{\rightarrow}$|
b) |$\underset{AB}{\rightarrow}$ - $\underset{AC}{\rightarrow}$|
c) |$\underset{AB}{\rightarrow}$ + $\underset{AC}{\rightarrow}$|
a) |$\underset{AB}{\rightarrow}$ + $\underset{BC}{\rightarrow}$| = a
b) |$\underset{AB}{\rightarrow}$ - $\underset{AC}{\rightarrow}$| = a
c) |$\underset{AB}{\rightarrow}$ + $\underset{AC}{\rightarrow}$| = a$\sqrt{a}$