What is the value of a in this circle's general form? I can find missing values a lot easier when circle's are in standard form, but some help with this would be great!

Question

anonymous · Answer

attachment

anonymous · Answer

8

anonymous · Answer

The center of the circle is (-4,2) and in standard form the circle is given by the equation$$(x+4)^2+(y-2)^2=2^2$$

anonymous · Answer

Oh okay! Thank you for putting it into standard form

anonymous · Answer

Also, do you know how to fin the eccentricity of an ellipse?

anonymous · Answer

This one for example

anonymous · Answer

Have you tried finding the ratio c/a

anonymous · Answer

C would be the center right? And would A be a point on the circle?

anonymous · Answer

Is it $$\frac{ \sqrt{3} }{ 2 }$$

anonymous · Answer

Here is used the formula $$\frac{ (x-h)^2 }{a^2}+\frac{(x-k)^2}{b^2}=1$$ and $$eccentricity = \sqrt{\frac{ a^2-b^2 }{ a }}$$