So, even if the speed is constant, that means, even if a lengthof the velocity vector stays the same, the velocity vector can still rotate.
因此即使速率不变,也就是说速度矢量的的大小不变,但它的方向可以做旋转。
2
For instance, it's also the square of the Euclidean norm on R2, the lengthof a two-dimensional vector, a part of the triangle inequality, and quite a bit more.
例如,R 2 的平方、二维向量的长度、三角不等式等都存在勾股定理。
3
Consider a vectorof five strings; you want to sort them on the basis of increasing string length.