If the circle and x-axis are tangential then the centre of the circle must be at a distance equal to the radius away from the x-axis. That is, the centre of the circle must lie on y = ±r (where r = radius) so that the coordinates of the centre are (a, ±r)
So the equation of the set of circles is
(x - a)2 + (y ± r)2 = r2
Differentiating gives
2*(x - a) + 2*(y ± r)*dy/dx = 0
(x - a) + (y ± r)*dy/dx = 0
so that
dy/dx = (a - x)/(y ± r)
It is not clear why you would want the differential equation, but you asked for it so you've got it!
dy/dx = (r - x)/sqrt(2xr - x2) , I hope!
Tangent circles are circles that touch one another without crossing. The distance between the centres of the circles must be equal to the difference or the sum of their radii.
No, tangent circles do not have the same center. They just touch at the side. Here is an example:
If the two circles are tangent to each other,then it must be at the same point.
No; tangent circles touch each other at one point but concentric circles cannot not touch.
[1+(y')2]3 = [yy"+1+(y')2]2
Yes.
dy/dx = (r - x)/sqrt(2xr - x2) , I hope!
Tangent circles are circles that touch one another without crossing. The distance between the centres of the circles must be equal to the difference or the sum of their radii.
No, tangent circles do not have the same center. They just touch at the side. Here is an example:
If the two circles are tangent to each other,then it must be at the same point.
No; tangent circles touch each other at one point but concentric circles cannot not touch.
Yes, circles that share one and only one point are tangent to each other.
Yes, it can as long as it is not the tangent line of the outermost circle. If it is tangent to any of the inner circles it will always cross the outer circles at two points--so it is their secant line--whereas the tangent of the outermost circle is secant to no circle because there are no more circles beyond that last one.
Tangent circles.
... touches each circle in exactly one point on each circle. given any two circles where none is entirely inside or inside and tangent to the other, there are at most four straight lines that are tangent to both circles.
An external tangent is a line that is tangent to both circles but does not pass between them.