# Help with polar coordinates

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#1
Hi, my teacher didn't explain this well to me at all and I actually have no idea where to even start with this question

The cartesian equation of a circle is (x+8)^2 + (y-6)^2 = 100

Using the origin O as the pole and the positive x-axis as the initial line, find the polar equation of this circle, giving your answer in the form r = psin0 + qcos0

(0 in this case is theta, not the number zero)

PLEASE DO NOT JUST GIVE ME AN ANSWER!!!! I NEED TO UNDERSTAND THIS!!!

Thanks
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#2
bump AQA FP3
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6 years ago
#3
(Original post by pryngles)
Hi, my teacher didn't explain this well to me at all and I actually have no idea where to even start with this question

The cartesian equation of a circle is (x+8)^2 + (y-6)^2 = 100

Using the origin O as the pole and the positive x-axis as the initial line, find the polar equation of this circle, giving your answer in the form r = psin0 + qcos0

(0 in this case is theta, not the number zero)

PLEASE DO NOT JUST GIVE ME AN ANSWER!!!! I NEED TO UNDERSTAND THIS!!!

Thanks
In the polar coordinate system each point on a plane is determined by a distance from a fixed point and an angle from a fixed direction.
The fixed point is called the pole, and the ray from the pole in the fixed direction is the polar axis.
The distance from the pole is called the radial coordinate or radius (), and the angle is the angular coordinate, polar angle, or azimuth ().

Draw a Cartesian coordinate system. According to the question, use the origin
as the pole and the positive x-axis as polar axis and draw a point on the plane
with the 2 polar coordinates and the angle of between
the ray passing throw the point and the polar axis.

Project the point on the axis X and Y and find the value of x and y in funtion of
and

Substitute them in the Cartesian equation of the circle.
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