Well, at point P, the velocity vector QP is perpendicular to the line QP, 1 so the sine of that angle is one.

点P，速度向量,垂直于直线，所以该角的正弦值为。

youdao

Well, at point P, the velocity vector QP is perpendicular to the line QP, 1 so the sine of that angle is one.

点P，速度向量,垂直于直线，所以该角的正弦值为。

youdao