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# polar coordinates watch

1. a) for the following curve r = 2 + cosΘ-cos2Θ

identify with proof any lines of symmetry.

b)find the cartesian equations of the curves with the following polar co ordinates
i)r = acos2Θ
ii)r = 4/3+ cosΘ

for a) how do you use the rule f(Θ) = f(2x-Θ)

I don't know how to do b
2. (Original post by bl64)
a) for the following curve r = 2 + cosΘ-cos2Θ

identify with proof any lines of symmetry.

b)find the cartesian equations of the curves with the following polar co ordinates
i)r = acos2Θ
ii)r = 4/3+ cosΘ

for a) how do you use the rule f(Θ) = f(2x-Θ)

I don't know how to do b
For b, use the identities r^2 = x^2 + y^2, x = rcos(theta) and y = rsin(theta) as well as the double angle formula
3. (Original post by 13 1 20 8 42)
For b, use the identities r^2 = x^2 + y^2, x = rcos(theta) and y = rsin(theta) as well as the double angle formula
thanks that really helped

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Updated: October 22, 2015
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