Saved Bookmarks
| 1. |
Is | \(\vec a-\vec b\) | greater than or less than | \(\vec a\) | + | \(\vec b\) |? |
|
Answer» \({|\vec a-\vec b|}^2-{(|\vec a|+|\vec b|)}^2\) ⇒\(|\vec a|^2+|\vec b|^2-2\,|\vec a|\,|\vec b|\,cos\, \theta-|\vec a|^2-|\vec b|^2-2|\vec a||\vec b|\) ⇒-4| a | | b | \(cos^2\frac{\theta}{2}\) = a negative quantity Hence, \(|\vec a- \vec b|<|\vec a|+|\vec b|\) |
|