Convert the polar equation to rectangular coordinates.

Solved it 

Initial Question:

$sec(\theta )=2$

Convert it to cosine

$cos(\theta)=\frac{1}{2}$

Which means

$\theta = \pm \frac{\pi}{3}$

$tan(\theta)=\pm\frac{\sqrt{3}}{1}=\pm\sqrt{3}$

$\frac{y}{x}=\pm\sqrt{3}$

Final answer is.

$y=\pm\sqrt{3}x$

sec(θ)=2

r/x  = 2

sqrt [ x^2 + y^2] / x  = 2

sqrt [ x^2 + y^2 ]  = 2x     square both sides

x^2 + y^2  = 4x^2

y^2  = 3x^2         take the square root of both sides

y =  ±√(3)x