Ellipse: x 2/a 2+y 2/b 2 =1(X axis) (a>b>0)

X 2/B 2+Y 2/A 2 =1(Y axis) (a>b>0)

e = c/a(0 & lt； e & lt 1)

Chord length formula: chord length = │ x1-x2 │√ (k 2+1) = │ y1-y2 │ [(1/k 2)+1].

Hyperbola: x 2/a 2-y 2/b 2 =1(x axis)

Y 2/A 2-X 2/B 2 = 1 (Y axis)

Asymptote: y = b/a (x axis)

Y = a/b (y axis)

b/a=√(e^2- 1)=√(c^2-a^2)/a^2=√(c/a)^2- 1

y^2=2px(p>； 0)

The straight line passing through the focus intersects the parabola at two points:

x 1*x2=p^2/4y 1*y2=-p^2