Lingaku- (math.) unit tangent vector
Generated: This term refers to a mathematical vector that is tangent to a curve at a given point and has a length of one. It is used in calculus and geometry to describe the direction of the curve at that point.
zài在qū xiàn曲线de的mǒu某yī diǎn一点，dān wèi qiē xiàng liàng单位切向量zhǐ xiàng指向gāi该diǎn点de的qiē xiàn切线fāng xiàng方向。
At a certain point on the curve, the unit tangent vector points in the direction of the tangent line at that point.