Question

Cho 6 điểm A, B, C, D, E, F. Chứng minh

a) AB+ CD+ BC+ EA = ED

b) AB+ BC+ CD+ FE+ DF= AE

Giúp mik vs ạ

Answer 1

Chắc là toàn vecto???

a/ \(=\left(\overrightarrow{EA}+\overrightarrow{AB}\right)+\left(\overrightarrow{BC}+\overrightarrow{CD}\right)=\overrightarrow{EB}+\overrightarrow{BD}=\overrightarrow{ED}\)

b/ \(=\left(\overrightarrow{AB}+\overrightarrow{BC}\right)+\overrightarrow{CD}+\left(\overrightarrow{DF}+\overrightarrow{FE}\right)\)

\(=\overrightarrow{AC}+\overrightarrow{CD}+\overrightarrow{DE}=\overrightarrow{AD}+\overrightarrow{DE}=\overrightarrow{AE}\)