If A ( x1, y1) and B( x2, y2,), then distance d, from A to B =
y = mx + cy - y1 = m(x - x1)
If two lines are parallel, then they have the same gradient.
If two lines are perpendicular, then the product of the gradients of the two lines is -1.
or: perpendicular gradient = -1/m where m is the gradient of the line perpendicular to it.
The general equation of a circle is
(x - h)2 + (y - k)2 = 0
The equation of a circle whose centre is the origin and whose radius is a is given by the equation
x2 + y2 = a2
x2 + y2 + 2gx + 2fy + c = 0
where the centre is (-g,-f) and radius is
The equation of a circle whose one diameter is the line segment joining the points
(x1, y1), (x2, y2) is given by
(x - x1)(x - x2) + (y - y1)(y - y2) = 0
y - 4 = 2(x - 1)
y - 4 = 2x - 2
y = 2x + 2
Additional Math >