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anonymous
 one year ago
PLEASE HELP!!!!
Determine if the graph is symmetric about the xaxis, the yaxis, or the origin.
r = 5 + 4 cos θ
anonymous
 one year ago
PLEASE HELP!!!! Determine if the graph is symmetric about the xaxis, the yaxis, or the origin. r = 5 + 4 cos θ

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Because of the 5 and 4, you can see that r takes values between 54=1 and 5+4=9. At theta=0 (and theta=2pi), r=9. At theta=pi (halfway the period), r=. What does this tell you about possible symmetries?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0its not even so it isnt around the x axis. right?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0@ZeHanz can you finish helping me please?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Well, the graph cannot be symmetrical around the origin, because of this. Also, because (9,0) and (1,0) are the points for theta=0 and theta=pi, the yaxis is not an axis of symmetry. So maybe the only symmetry left is the xaxis. Because the values of the cosine are the same before and after pi, this is indeed the case. This is what the graph roughly looks like:

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0okay? so then how can you tell if it is around the x axis?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Because the points above the xaxis belong to theta between 0 and pi, and the points below to theta between pi and 2pi. The cosine has the same values before and after pi, so the points lie symmetrical with respect to the xaxis. (Hope you understand what I want to say...)
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