- #1

My question is that according to this √-1×√-1=1.but it does not hold good in case of i(complex number).

I.e i^2 =-1. Why???

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- Thread starter Gourav kumar Lakhera
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- #1

My question is that according to this √-1×√-1=1.but it does not hold good in case of i(complex number).

I.e i^2 =-1. Why???

- #2

Mark44

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No, this is not true. ##\sqrt{-5} = i\sqrt{5}## so ##\sqrt{-5} \cdot \sqrt{-5} = i^2 (\sqrt{5})^2 = -5##, not 5 as you show above.As we know that √-5×√-5=5

This isn't true, either, for the same reason as above.Gourav kumar Lakhera said:i.e multiplication with it self

My question is that according to this √-1×√-1=1

Gourav kumar Lakhera said:.but it does not hold good in case of i(complex number).

I.e i^2 =-1. Why???

You are apparently using the rule that ##\sqrt a \sqrt b = \sqrt{ab}##. That rule holds only when both a and b are nonnegative real numbers.

- #3

Thnkuu buddy

- #4

fresh_42

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https://www.physicsforums.com/insights/things-can-go-wrong-complex-numbers/

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