Which is the parametric form of the polar equation r=-3theta

A.x=3thats cos theta

Y=3theta sin theta

B.x=-3theta cos theta

Y=-3theta sin theta

C.x=-3cos theta

Y=-3 sin theta

D.x=-theta cos theta

Y=-theta sin theta

Respuesta :

Answer:B

Step-by-step explanation:

Given

[tex]r=-3\theta [/tex]

so [tex]x=-3\theta \cos \theta \quad \ldots(i)[/tex]

and

[tex]y=-3\theta \sin \theta \quad \ldots(ii)[/tex]

squaring and adding [tex](i)[/tex] and [tex](ii)[/tex] we get

[tex]x^2+y^2=(-3\theta \cos \theta)^2+(-3\theta \sin \theta)^2[/tex]

[tex]x^2+y^2=r^2=9\theta ^2\cos ^2 \theta +9\theta ^2\sin ^2 \theta [/tex]

[tex]r^2=9\theta ^2[/tex]

[tex]r=-3\theta [/tex]

for [tex]r[/tex] to be negative both [tex]x[/tex] and [tex]y[/tex] must be negative