How do you write the equation for a circle having (3,0) and (-2,-4) as ends of a diameter?

1 Answer
Aug 31, 2016

Equation of circle is x^2+y^2-x+4y-6=0x2+y2x+4y6=0

Explanation:

As the end points of diameter are (3,0)(3,0) and (-2,-4)(2,4), the center is their midpoint i.e. ((3-2)/2,(0-4)/2)(322,042) or (1/2,-2)(12,2).

The distance between (3,0)(3,0) and (-2,-4)(2,4) will be

sqrt((3-(-2))^2+(0-(-4))^2)(3(2))2+(0(4))2

= sqrt(25+16)25+16

= sqrt4141

Hence diameter is sqrt4141 and radius sqrt41/2412.

As the center is (1/2,-2)(12,2) and radius is sqrt41/2412, the equation of circle is

(x-1/2)^2+(y+2)^2=(sqrt41/2)^2(x12)2+(y+2)2=(412)2 or

x^2-x+1/4+y^2+4y+4=41/4x2x+14+y2+4y+4=414 or

x^2+y^2-x+4y+4+1/4-41/4=0x2+y2x+4y+4+14414=0 or

x^2+y^2-x+4y+4-10=0x2+y2x+4y+410=0 or

x^2+y^2-x+4y-6=0x2+y2x+4y6=0