短語詞組短語tangent -line approximation 切線法估值tangent t line 切線main tangent -line height of terminal-drum 滾筒母切線高度Derivative and Tangent Line 微分和切線length of tangent line 切線的長;切線長;切線長度Tangent line TL 切線Tangent and Normal line 切線和法線tangent line coordinate system 切線坐標(biāo)系 返回 tangent line