Given:
Center of a circle is at point C(-1,2).
AB is the diameter of the circle.
Coordinates of the point A are A(2,6).
To find:
The coordinates of point B.
Solution:
Let the coordinates of point B are (a,b).
If AB is the diameter of the circle, then A and B are end points of diameter of the circle and the center C is the midpoint of AB.
[tex]Midpoint=\left(\dfrac{x_1+x_2}{2},\dfrac{y_1+y_2}{2}\right)[/tex]
Point C = Midpoint of AB
[tex](-1,2)=\left(\dfrac{2+a}{2},\dfrac{6+b}{2}\right)[/tex]
On comparing both sides, we get
[tex]\dfrac{2+a}{2}=-1[/tex]
[tex]2+a=-1\times 2[/tex]
[tex]a=-2-2[/tex]
[tex]a=-4[/tex]
Similarly,
[tex]\dfrac{6+b}{2}=2[/tex]
[tex]6+b=2\times 2[/tex]
[tex]b=4-6[/tex]
[tex]b=-2[/tex]
Therefore, the coordinates of point B are (-4,-2).
