And now, delta r should be essentially roughly equal to, well, its direction will be tangent to the trajectory.

这里，△r应该是近似等于。。。,它的方向是轨道的切线方向。

youdao

And now, delta r should be essentially roughly equal to, well, its direction will be tangent to the trajectory.

这里，△r应该是近似等于。。。,它的方向是轨道的切线方向。

youdao