If the center of circle C is on the straight line 5x-3y = 8 and circle C is tangent to two coordinate axes, the equation of circle C is

If the center of circle C is on the straight line 5x-3y = 8 and circle C is tangent to two coordinate axes, the equation of circle C is


Let the center of the circle be (x, y) tangent to the two coordinate axes, then | x | = R, | y | = RX = y = R or x = - y = R or - x = - y = R or - x = y = R. the center of the circle is on the straight line 5x-3y = 8 when x = y 5x-3x = 8, x = 4, y = 4, radius = | x | = 4 when x = - y 5x + 3x = 8, x = 1, y = - 1, radius = | x | = 1, so the equation of the circle is (x-1) & | 178; + (y + 1) & | 178; = 1



The standard equation for a circle whose center is on a straight line 5x-3y = 8 and tangent to two coordinate axes


If x = y, then x = y = 4; if x = - y, then x = 1, y = - 1, then the center of the circle is (4,4) or (1, - 1) because the radius is the distance from the center of the circle to the tangent line, that is, the center of the circle is (4,4)



The equation of a circle passing through point a (8,1) and tangent to two coordinate axes


Obviously, the circle passing through point (8,1) is located in the first quadrant. Let the equation of the circle be (x-a) & sup2; + (Y-A) & sup2; = A & sup2;, and a > 0 be substituted into point (8,1) to get (8-A) & sup2; + (1-A) & sup2; = A & sup2; that is, a & sup2; - 18a + 65 = 0, that is, (A-13) (a-5) = 0 to get a = 13 or a = 5. The circle is (X-13) & sup2; + (1-A) & sup2; = A & sup2