The equation of a circle whose center is on the parabola y ^ 2 = 4x (Y > 0) and is tangent to the Quasilinear and x-axis of the parabola is

The equation of a circle whose center is on the parabola y ^ 2 = 4x (Y > 0) and is tangent to the Quasilinear and x-axis of the parabola is


The directrix of the parabola y & #178; = 4x is x = - 1. If the circle is tangent to the parabola directrix, then the distance from the center of the circle to the directrix is equal to the radius of the circle, and the distance from the center of the circle to the directrix is equal to the distance from the center of the circle to the focus, then the circle passes through the focus F of the parabola



The equation of a circle whose center is on the parabola y2 = 2x (Y > 0) and tangent to the Quasilinear and x-axis of the parabola is ()
A. x2+y2−x−2y−14=0B. x2+y2+x-2y+1=0C. x2+y2-x-2y+1=0D. x2+y2−x−2y+14=0


Let the coordinates of the center of the circle be (B22, b), then B22 + 12 = B & nbsp; can be obtained from the tangent of the circle to the Quasilinear and x-axis of the parabola; so B = 1, so the center of the circle is (12, 1) radius r = 1, so the equation of the circle whose center is on the parabola y2 = 2x (Y > 0) and tangent to the Quasilinear and x-axis of the parabola is (x − 12) 2 + (Y − 1) 2 & nbsp; = 1, that is, X2 + Y2 − x − 2Y + 14 = 0, so D is selected



The equation of a circle whose center is on the parabola y2 = 2x and tangent to the Quasilinear and x-axis of the parabola is


Let the center of the circle be m (x, y), then
Y = √ 2x, i.e. m (x, √ 2x)
The circle m is tangent to the directrix and x-axis
The inverted x-axis of M is equal to the distance to the guide line
∴x+1/2=√2x
∴x=1/2,y=±1
The circular equation is (x-1 / 2) &# 178; + (Y ± 1) &# 178; = 2



The equation of a circle whose center is on the parabola y = 2x and tangent to the x-axis and the Quasilinear of the parabola is?


There are two sets of solutions to this problem. If this point satisfies the meaning of the problem, then there is √ 2x = x + - 1 / 2 | 2x = x + X + 1 / 4, and the solution is x = 1 / 2, so y = √ (2 × 1 / 2) = 1, r = x + 1 / 2 = 1. The equation of the circle is (x-1 / 2) + (Y-1) = 1 (2) P (x, √ 2x) is the point of the parabola at the bottom of the x-axis, If this point satisfies the meaning of the problem, then the solution of | - √ 2x = x + | - 1 / 2 | 2x = x + X + 1 / 4 is x = 1 / 2, so y = - √ (2 × 1 / 2) = - 1, r = | - √ 2X = 1, and the equation of circle is (x-1 / 2) + (y + 1) = 1