Question

Find an equation of the circle that satisfies the stated conditions. (Give your answer in standard notation.)
Tangent to both axes, center in the second quadrant, radius 3

Answer 1

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Answer 2

Equation of a circle
\[ (x+a)^2 + (y+b)^2 = r^2\]

We make r = 3 so that it can have radius 3
\[ (x+a)^2 + (y+b)^2 = 3^2\]

Then we translate it up and left by the radius (3) to make it tangent to each axis
\[ (x+3)^2 + (y-3)^2 = 3^2\]


Observe:
http://www.wolframalpha.com/input/?i=%28x%2B3%29%5E2+%2B+%28y-3%29%5E2+%3D+3%5E2

Answer 3

Remember that increasing a shifts it left and increasing b shifts it down.

Answer 4

thanks :)