EquationEquation GraphGraph FocusFocus Length of LRLength\space of\space LR DirectrixDirectrix Length of Major AxisLength\space of\space Major\space Axis
x2a2 +y2b2 =1\frac{x^2}{a^2}\space+\frac{y^2}{b^2}\space=1
a>ba>b
(±ae,0)(±ae,0) 2b2a\frac{2b^2}{a} x=±aex=±\frac{a}{e} 2a2a
x2a2 +y2b2 =1\frac{x^2}{a^2}\space+\frac{y^2}{b^2}\space=1
a<ba < b
(0,±be)(0,±be) 2a2b\frac{2a^2}{b} y=±bey=±\frac{b}{e} 2b2b

Equations of Tangent of Ellipse

EquationEquation Parametric CoordinatesParametric\space Coordinates Equation of tangentEquation\space of\space tangent Condition of TangencyCondition\space of \space Tangency
x2a2 +y2b2 =1\frac{x^2}{a^2}\space+\frac{y^2}{b^2}\space=1
a>ba>b
(acosθ,bsinθ)(acos\theta,bsin\theta) y=mx±am2+b2y=mx±\sqrt{am^2+b^2}
xcosθa+ysinθb=1\frac{xcos\theta}{a}+\frac{ysin\theta}{b}=1
c=±am2+b2c=±\sqrt{am^2+b^2}
x2a2 +y2b2 =1\frac{x^2}{a^2}\space+\frac{y^2}{b^2}\space=1
a<ba < b
(bcosθ,asinθ)(bcos\theta,asin\theta) y=mx±bm2+a2y=mx±\sqrt{bm^2+a^2}
xcosθb+ysinθa=1\frac{xcos\theta}{b}+\frac{ysin\theta}{a}=1
c=±bm2+a2c=±\sqrt{bm^2+a^2}

Equations of Normal of Ellipse

EquationEquation Parametric CoordinatesParametric\space Coordinates Equation of NormalEquation\space of\space Normal Condition of NormalityCondition\space of \space Normality
x2a2 +y2b2 =1\frac{x^2}{a^2}\space+\frac{y^2}{b^2}\space=1
a>ba>b
(acosθ,bsinθ)(acos\theta,bsin\theta) axcosθbysinθ=a2b2\frac{ax}{cos\theta}-\frac{by}{sin\theta}=a^2-b^2 c=±m(a2b2)a2+b2m2c=±\frac{m(a^2-b^2)}{\sqrt{a^2+b^2m^2}}
x2a2 +y2b2 =1\frac{x^2}{a^2}\space+\frac{y^2}{b^2}\space=1
a<ba < b
(bcosθ,asinθ)(bcos\theta,asin\theta) bxcosθaysinθ=b2a2\frac{bx}{cos\theta}-\frac{ay}{sin\theta}=b^2-a^2 c=±m(b2a2)b2+a2m2c=±\frac{m(b^2-a^2)}{\sqrt{b^2+a^2m^2}}

Equations of Director circle of Ellipse

EquationEquation Equation of Director CircleEquation\space of\space Director\space Circle
x2a2 +y2b2 =1\frac{x^2}{a^2}\space+\frac{y^2}{b^2}\space=1
a>ba>b
x2+y2 =a2+b2x^2\,+\,y^2\space=\,a^2\,+\,b^2
x2a2 +y2b2 =1\frac{x^2}{a^2}\space+\frac{y^2}{b^2}\space=1
a<ba < b
x2+y2 =a2+b2x^2\,+\,y^2\space=\,a^2\,+\,b^2