It is known that the center coordinate of the circle is (- 1,2) and tangent to the line 2x + Y-5 = 0 at point M. the standard equation of the circle is obtained
Solution:
Because the circle is tangent to the line,
Then the distance from the center of the circle to the straight line is the radius:
D = | - 2 + 2-5 | / radical (1 + 4)
=Root 5
So the equation of the circle is:
(x+1)^2+(y-2)^2=5
The standard equation is:
x^2+2x+y^2-4y=0
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