- #1

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Can square root of 4 be +2 or -2?

I asked that to my math teacher so he said: NO, square root of 4 is +2!

But I can't really understand why it cannot be -2 since -2 squared is also 4. One thing I've imagined is: square root of 4 can be +2 or -2, but for CONVENTION we use +2. Is that right?

There's another question related to that: consider

[tex]i^2 = -1[/tex]

squaring the two sides we obtain

[tex]i^4 = 1[/tex]

so

[tex]i = 1[/tex]

so: can the i (the imaginary number) be 1? I think I'm making a lot of confusion with that, could someone explain me that?

Thank you