Question

Rewrite the parametric equations without the parameter t:
x=sect and y=4tant
A. x^2+y^2/4=1
B. x^2-y^2/16=1
C. x^2/16+y^2=1
D. x^2-y^2=16

Answer 1

note that sec^2 t = 1 + tan^2 t
So,
x^2 = (y/4)^2 + 1
now finish it off

Answer 2

From that, I got x^2=y^2/16+1. Than, to isolate the 1, I subtracted y^2/16 from each side of the equation to get B: x^2-y^2/16=1.
@ Oobleck, thank you for your help.