1.

Find the equation of the circle of radius 5 cm, whose centre lies on the lies on the y-axis and which passes through the point ` (3, 2 )`

Answer» Correct Answer - ` (x ^(2) + y ^(2) - 12y + 11 =0 ) or (x ^(2) + y ^(2) + 4y - 21=0 )`
Let the centre of the circle be `C( 0, k)`
It is given that the circle passes through ` P(3, 2)`
Then `, |CP|^(2) = 5^(2) hArrf (0 - 3) ^(2) + ( 2 - k ) ^(2) = 5^(2)`
`" " hArr ( 2- k ) = pm 4 hArr k = 6 or k = - 2 `
` therefore ` the centre of the circles is ` (0, 6) or (0, - 2 )`
Hence, the equation of the circle is
` " "[(x - 0) ^(2) + ( y - 6) ^(2) = 5^(2) ] or [ ( x - 0 ) ^(2) + (y + 2 ) ^(2) = 5 ^(2) ] `.


Discussion

No Comment Found

Related InterviewSolutions