tangent-line approximation切线法估值
tangent t line切线
main tangent-line height of terminal-drum滚筒母切线高度
Derivative and Tangent Line微分和切线
length of tangent line切线的长;切线长度;切线长
Tangent line TL切线
Tangent and Normal line切线和法线
tangent line coordinate system切线坐标系