A circle passes through - 2 , 4 and touches the y - axis at 0 , 2 . Which one of the following equations can…

A circle passes through -2,4 and touches the y-axis at 0,2. Which one of the following equations can represent a diameter of this circle ?
  1. 2x-3y+10=0
  2. 3x+4y-3=0
  3. 4x+5y-6=0
  4. 5x+2y+4=0

Solution

As y-axis is tangent to the circle therefore the centre of the circle would be x,2 and distance of centre from 0,2 and -2,4 should be equal.

h2+02=h+22+22

h2=h2+4h+4+4

h=-2

Hence, centre is -2,2.

2x-3y+10=0 is the diameter, as centre lies on it.

Asked in: JEE Main 2016 (09 Apr Online)

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