View attachment 131523
Chỉ mình các bài này với ạ
Bài 21:
a, Ta có: [tex]2\overrightarrow{IA}+3\overrightarrow{IB}=\overrightarrow{0}\\\Rightarrow \overrightarrow{AI}=\frac{2\overrightarrow{AA}+3\overrightarrow{AB}}{5}\\\Rightarrow \overrightarrow{AI}=\frac{3}{5}\overrightarrow{AB}[/tex]
b, [tex]2\overrightarrow{IA}+3\overrightarrow{IB}=\overrightarrow{0}\\\Rightarrow \overrightarrow{MI}=\frac{2\overrightarrow{MA}+3\overrightarrow{MB}}{5}=\frac{2}{5}\overrightarrow{MA}+\frac{3}{5}\overrightarrow{MB}[/tex]
Bài 22:
a, Ta có: [tex]\overrightarrow{MB}=2\overrightarrow{CM}\\\Rightarrow \overrightarrow{MB}-2\overrightarrow{CM}=0\\\Rightarrow \overrightarrow{MB}+2\overrightarrow{MC}=0\\\Rightarrow \overrightarrow{AM}=\frac{\overrightarrow{AB}+2\overrightarrow{AC}}{3}[/tex]
b, Ta có: [tex]\overrightarrow{KA}+\overrightarrow{KB}+\overrightarrow{KC}=3\overrightarrow{KG}\\\Rightarrow \overrightarrow{KA}+\overrightarrow{KB}+\overrightarrow{KC}-6\overrightarrow{KB}=0\\\Rightarrow \overrightarrow{KA}-5\overrightarrow{KB}+\overrightarrow{KC}=0[/tex]
Bài 23:
[tex]\overrightarrow{KQ}+\overrightarrow{KP}=0\\\Rightarrow \overrightarrow{AK}=\frac{\overrightarrow{AQ}+\overrightarrow{AP}}{2}\\\Rightarrow \overrightarrow{AK}=\frac{\frac{1}{3}\overrightarrow{AC}+\frac{1}{2}\overrightarrow{AB}}{2}=\frac{1}{6}\overrightarrow{AC}+\frac{1}{4}\overrightarrow{AB}[/tex]