Circles (VCE SSCE Mathematical Methods): Flashcards

Set of all points equidistant from fixed point (centre)

$(x - h)^2 + (y - k)^2 = r^2$, centre $(h,k)$, radius $r$

$x^2 + y^2 = 1$

Set $x = 0$ and solve for $y$

Set $y = 0$ and solve for $x$

$x^2 + y^2 - 2hx - 2ky + c = 0$

Coefficients of $x^2$ and $y^2$ both 1, no $xy$ term

$y = +\sqrt{r^2 - x^2}$

$y = -\sqrt{r^2 - x^2}$

Centre coords appear with opposite signs