Question

Determine if the graph is symmetric about the x-axis, the y-axis, or the origin.

r = -5 - 5 cos θ

Answer 1

had u made the graph of that?

Answer 2

No, I was told to do it without making a graph :/

Answer 3

ok so to test for symmetric about the x axis u must replace
(theta) by (-theta) and see if u get the same equation

Answer 4

-5-5cos- θ ?

Answer 5

i cant write theta so i will write (t) instead
-5 - 5cos(t)
replacing t by -t
-5-5cos(-t)
given that cos(-t) = cos(t)
-5-5cos(-t) = -5-5cos(t)
so the graph is symetric about the x axis

Answer 6

What If i had r = 5 cos 3θ instead?

Answer 7

it is the same have u tried to replace theta by -theta?

Answer 8

5cos(3t)
then replace
5cos(-3t)
5cos(-3t) = 5cos(3t)
symetric about the x axis?

Answer 9

yes

Answer 10

Thank you :)

Answer 11

here r the test for symetry in polar coordinates
http://www.saylor.org/site/wp-content/uploads/2011/04/GRAPHING-IN-POLAR-COORDINATES.pdf