Let \(u\) and \(v\) be two non zero vectors, if \(|u+v|=|u-v|\), then
Let \(u\) and \(v\) be two non zero vectors, if \(|u+v|=|u-v|\), then
- \(u\) and \(v\) have the same direction
- \(u\) and \(v\) are perpendicular
- \(u\) and \(v\) have the opposite direction
- Data Insufficient
Solution
\(|\mathrm{u}+\mathrm{v}|=|\mathrm{u}-\mathrm{v}|\)
Squaring on both sides,
\(\begin{aligned}
|\mathrm{u}+\mathrm{v}|^2 & =|\mathrm{u}-\mathrm{v}|^2 \\
|\mathrm{u}|^2+|\mathrm{v}|^2+\overline{\bar{u} v} & =|\mathrm{u}|^2+|\mathrm{v}|^2+2(\bar{u} v) \\
4(\bar{u} \cdot \bar{v}) & =0 \\
\bar{u}, v & =0 \\
\bar{u} & \perp \bar{v}
\end{aligned}\)
Hence, option (b) is correct.
Asked in: AP EAMCET 2020 (18 Sep Shift 2)
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