Creating a Circle through an graph equation?
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On the graphing calculator I have, it doesn't come with drawing primitives and I seem to have forgotten the equation for a cirlce. e.g. y=(forgot what goes here).
ONE form of the Cartesian Equation for a circle is;
(x-a)^2 + (y-b)^2 = r^2
where (a,b) denotes the CENTRE of the circle and r denotes the RADIUS of the circle. (x, y) would denote the actual pixel plot on the screen.
The Parametric Equations of a circle, which for programming would perhaps be more useful, are;
x = rcosA + a
y = rsinA + b
where A denotes the ANGLE of the radial line.
Not really a whizz on this forum (but I sure know my math), cos I don't use it much... Otherwise, I'd show you a graphic that perfectly shows how these equations work.
One bit of optimization advice... If u need it that is... Is to try and use Trigonometric tables which hold the pre-computed values of cosA and sinA, as the angle A ranges from 0 - 360 degrees... Or 0 - 2*pi radians!
Hope this helps... If your still a bit confused... I'll try and send u a graphic :-)
(x-a)^2 + (y-b)^2 = r^2
where (a,b) denotes the CENTRE of the circle and r denotes the RADIUS of the circle. (x, y) would denote the actual pixel plot on the screen.
The Parametric Equations of a circle, which for programming would perhaps be more useful, are;
x = rcosA + a
y = rsinA + b
where A denotes the ANGLE of the radial line.
Not really a whizz on this forum (but I sure know my math), cos I don't use it much... Otherwise, I'd show you a graphic that perfectly shows how these equations work.
One bit of optimization advice... If u need it that is... Is to try and use Trigonometric tables which hold the pre-computed values of cosA and sinA, as the angle A ranges from 0 - 360 degrees... Or 0 - 2*pi radians!
Hope this helps... If your still a bit confused... I'll try and send u a graphic :-)
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