Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

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Hi;

I am sorry that I can not do better. There are people in here that would be better at answering questions of this type. Please wait for one of them to explain it better.

Hi;

The square root function does not easily extend beyond the non-negative reals. There may be examples where what you did holds but for all complex numbers it would not. Also, when we say √ 4 we just mean +2, the principal square root, not the -2.

So

√( -1)*√( -1) = √[( -1)( -1)]

you are not allowed to do that with two complex numbers.

Read this http://math.stackexchange.com/questions … stribution

, especially Lee Mosher's answer.

That is the reason you are always told when working with a negative inside there to pull out a square root of -1 and to write is as i.

Hi;

The next time you are confronted with two different solutions remember that each point given is a solution to the equation of the circle. So all you need to do to verify correctness is to plug in.

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only is true when

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Can you post an example?

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Therefore, the centre of the circle is (-2, 4).

The point (-2,4) is one of your given points that lie on the circle, it can not of course be on the circle and the center of the circle.

Hi;

I have checked the book answer, it is correct.

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Is there anymore to the question?

Hi;

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