x^2/a^2 + y^2/b^2

length[d]

+

=

\frac{x^2}{a^2} + \frac{y^2}{b^2} = 1

a = 7 (slider from 1 to 10, step 1)
b = 4 (slider from 1 to 10, step 1)
c: x^(2.0) / a^(2.0) + y^(2.0) / b^(2.0) = 1.0
C1 = If(a > b, (sqrt(a^(2.0) - b^(2.0)), 0.0), (0.0, sqrt(b^(2.0) - a^(2.0))))
C2 = If(a > b, (-sqrt(a^(2.0) - b^(2.0)), 0.0), (0.0, -sqrt(b^(2.0) - a^(2.0))))
P = Point(c)
d = Segment(P, C1)
e = Segment(P, C2)
text1 = Text(d)
text2 = Text(e)
text4 = Text(d + e)