Compare general equations expended form only of a circle par
Compare general equations (expended form only) of a circle, parabola and ellipse.
(in picture)
2.Compare the general form of equations of a circle and parabola.
3. Compare the general form of equations of a circle and ellipse.
Solution
Solution:
2.
As we know;
parabola: (xh)2=(yk)
1.A parabola with its vertex at ( h, k), opening vertically, will have the following properties.
2.The focus will be at(h,k+1/4a)
3.The directrix will have the equation y=k-1/4a
4.The axis of symmetry will have the equation x = h
and
Circle: (xh)2+(yk)2=r2
where r is the radius of the circle,
and h,k are the coordinates of its center
hence:
r2 - (yk)2 = (yk)
=> t2 + t - r2 = 0 (let,y-k =t)
=> t = (1/2)[-1±1 -4r2]
=> y = (1/2)[-1±1 -4r2] + k
intersection of these curves.
3.
As we know;
A circle can be defined as the locus of all points that satisfy the equation
(x-h)2 + (y-k)2 = r2
where r is the radius of the circle,
and h,k are the coordinates of its center.
whereas:
An ellipse can be defined as the locus of all points that satisfy the equation
x2/a2 + y2/b2 = 1
where: x,y are the coordinates of any point on the ellipse
and a, b are the radius on the x and y axes respectively
hence on comparing:
1.Distance between the center and any point on the circle is equal, but not in the ellipse
2.The two diameters of an ellipse are different in length, while, in a circle, the size of all the diameters is the same
3.The semi-major axis and semi-minor axis of an ellipse are different in length, while the radius is constant for a given circle

