Question

Which rectangular equation corresponds to these parametric equations?
x = 0.2sec t and y = -0.25tan t

A) 25x^2 − 16y^2 = 1
B) 25x^2 + 16y^2 = 1
C) x^2 − 16y^2 = 25
D) 25y^2 − 16x^2 = 1
E) 4x^2 − 16x^2 = 1

Answer 1

since sec^2 = 1+tan^2,

(x/.2)^2 = (y/-.25)^2 + 1
25x^2 - 16y^2 = 1

Looks like A to me