Proving the Equivalence of √(1) and √(-1)(-1)

In summary, the conversation discusses the correctness of the equation 1 = √(1), and how it can also be represented as √(-1)(-1) and (√-1)(√-1). It is pointed out that this may not always hold true due to the complex nature of squaring.
  • #1
Yh Hoo
73
0
1 = √(1)
= √(-1)(-1)
= (√-1)(√-1)
= i.i
= i[itex]^{2}[/itex]
= -1
Is this a correct equation??
anythings wrong with this?
i think theoretically it is correct but it seems like
√(1) = √(-1)(-1)
√(1) = √(1)(1) also!
so how to explain this??
 
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  • #2
Yh Hoo said:
1 = √(1)
= √(-1)(-1)
= (√-1)(√-1)
= i.i
= i[itex]^{2}[/itex]
= -1
Is this a correct equation??
anythings wrong with this?
i think theoretically it is correct but it seems like
√(1) = √(-1)(-1)
√(1) = √(1)(1) also!
so how to explain this??



Squaring is a double branched complex variable function, and thus "usual" properties in real numbers can fail miserably.

In this case the problem appears in the third equality: it isn't true without imposing certain restrictive conditions.

DonAntonio
 

1. How do you prove the equivalence of √(1) and √(-1)(-1)?

The equivalence of √(1) and √(-1)(-1) can be proven by using the definition of the square root function and basic algebraic manipulations. We can start by rewriting √(-1)(-1) as √(-1) * √(-1). Then, using the definition of the square root function, we know that √(-1) = i, where i is the imaginary unit. Therefore, √(1) and √(-1)(-1) both become i * i, which is equal to -1. This proves their equivalence.

2. Can you use any other methods to prove the equivalence of √(1) and √(-1)(-1)?

Yes, there are other methods that can be used to prove the equivalence of √(1) and √(-1)(-1). One method is to use the polar form of complex numbers, where we can represent √(1) and √(-1)(-1) as 1 * cis(0) and 1 * cis(π), respectively. Since cis(π) is equal to -1, this also proves their equivalence.

3. Why is it important to prove the equivalence of √(1) and √(-1)(-1)?

This equivalence is important because it helps us understand the properties of complex numbers and their relationship to real numbers. It also allows us to simplify complex expressions involving square roots and perform calculations more efficiently.

4. Can you provide a real-life application of this equivalence?

One real-life application of this equivalence is in electrical engineering, where complex numbers are used to represent alternating current (AC) circuits. By proving the equivalence of √(1) and √(-1)(-1), we can simplify calculations involving AC circuits and analyze their behavior more accurately.

5. Are there any limitations to this equivalence?

Yes, there are limitations to this equivalence. It only applies to the square root of -1 and cannot be generalized to other complex numbers. Additionally, it does not hold true for the square root of any other negative number, as their square roots would be imaginary and not equivalent to √(1).

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