a) |$\underset{AB}{\rightarrow}$ - $\underset{AC}{\rightarrow}$|
= a$\sqrt{41}$
b) |$\underset{AB}{\rightarrow}$ + $\underset{AC}{\rightarrow}$|
= a$\sqrt{41}$
Bài 38 : Cho tam giác ABC vuông tại A, AB = 4a, AC = 5a. Tính :
a) |$\underset{AB}{\rightarrow}$ - $\underset{AC}{\rightarrow}$|
b) |$\underset{AB}{\rightarrow}$ +$\underset{AC}{\rightarrow}$|
a) |$\underset{AB}{\rightarrow}$ - $\underset{AC}{\rightarrow}$|
= a$\sqrt{41}$
b) |$\underset{AB}{\rightarrow}$ + $\underset{AC}{\rightarrow}$|
= a$\sqrt{41}$