how can we find the points on a circle?

Question

we have a circle with the center ( x-center , y-center ) and the radius ( r-circle ).
so how can we find the end points on this circle ( x-end , y-end ).
for example x-center = 20 , y-center = 20 , r-circle = 10 , what is the x-end and y-end. ( ( x-center , y-center ) is the central point and ( x-end , y-end ) is on of the points on circumference )

Answer 1

Circular graph in basic form is y^2 = r^2 - x^2 where the center is at ( 0 , 0 ) and r is the radius.

Your graph goes like this (y - 20)^2 = 10^2 - (x - 20)^2

every n thick, (n is from 0 - 59)
endX = centerX+(radius*(cos(90-6n)) (90 in degrees)
endY = centerY+(radius*(sin(90-6n)) (90 in degrees)

:)

Answer 2

The general equation of a circle is:
(x-h)^2 + (y-k)^2 = r^2
h is what you called x-center
k is what you called y-center

To find the points on the circle, just plug in a value for x and you will come up with the 2 values of y, corresponding to the 2 points on the circle having the same x coordinate.

Remember though, that you can only use values of x such that h-r <= x <= h+r

Answer 3

A point is unique, only one.
But a line (whether straight or circular), consists of infinite number of points.
I think we can find these points by setting limits.