instant fan/medal
Which of the following polar equations produces the same graph as the Cartesian equation x^2 - y^2 = 16?

Question

czesc · Answer

r cos θ = 16
	r^2 cos θ = 16
	r = 4
	r^2 cos 2θ = 16

dumbcow · Answer

Use following relationships
$$x = r \cos \theta$$
$$y = r \sin \theta$$
$$\cos (2 \theta) = \cos^2 \theta - \sin^2 \theta$$

czesc · Answer

@dumbcow thank you so much, therefore it would be 	r^2 cos 2θ = 16
correct? I had never learned those relationships before, thank you again.

dumbcow · Answer

dumbcow · Answer