how does r=2cos3(theta) = r=2cos(theta)(cos(theta)^2-(3 sin(theta)^2)) in polar equations terms
I only just noticed "in polar form" so I am not sure what you need.
I can certainly show that they are the same.
You are actually asking me to show that
LHS=2[cos2\theta cos\theta-sin2\theta sin\theta]\\\\
LHS=2[(cos^2\theta-sin^2\theta) cos\theta-(2sin\theta cos\theta sin\theta)]\\\\
LHS=2cos\theta [cos^2\theta -sin^2\theta -2sin^2\theta ]\\\\
Thanks i think that should work i just have an investigation on Polar equations and the question was show how r=2cos3(theta) is euqal to ^2=2x^3-6xy^2
Knowing that (x^2+y^2)=r^2
Yes, that is right
But I still don't know how the answer should be set out :/
So then you just have to show that the other equation is the same ? (Which is easy to do)
So you need to work on both equations and get to the same polar equation. :/
I am still confused though. I understand the algebra, no problems, but I don't understand how it all goes together.
I am not explaining well because I am not quite sure what it is that I don't understand.
I just know that there is something that I don't quite get here.
Maybe a graph would help?