Complete the square for x: To find the center and radius of the circle, we need to complete the square for both x and y terms in the equation x2−2x+y2−4y−4=0.
Group x and y terms: First, we group the x terms and the y terms together: (x2−2x)+(y2−4y)=4.
Add values to complete square: Next, we complete the square for the x terms. We take half of the coefficient of x, which is −22=−1, square it to get 1, and add it to both sides of the equation: (x2−2x+1)+(y2−4y)=4+1.
Standard form of circle equation: Now, we complete the square for the y terms. We take half of the coefficient of y, which is −4/2=−2, square it to get 4, and add it to both sides of the equation: (x2−2x+1)+(y2−4y+4)=4+1+4.
Identify center and radius: After adding the necessary values to complete the square, we have: (x−1)2+(y−2)2=9.
Identify center and radius: After adding the necessary values to complete the square, we have: (x−1)2+(y−2)2=9.The equation (x−1)2+(y−2)2=9 is now in the standard form of a circle's equation, (x−h)2+(y−k)2=r2, where (h,k) is the center and r is the radius.
Identify center and radius: After adding the necessary values to complete the square, we have: (x−1)2+(y−2)2=9.The equation (x−1)2+(y−2)2=9 is now in the standard form of a circle's equation, (x−h)2+(y−k)2=r2, where (h,k) is the center and r is the radius.From the equation (x−1)2+(y−2)2=9, we can see that the center (h,k) of the circle is (1,2) and the radius r is the square root of 9, which is (x−1)2+(y−2)2=90.
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