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# Help: Proof that 1 = -1?

#### Shared by Yumin Wang 14, China · 1 year, 3 months ago

I came across something the other day involving complex numbers.

It is obvious that: $\frac {1}{ -1} = -1 = \frac {-1}{1}$.

If we take square roots on both sides, we get: $\frac {1}{i} = \frac {i} {1}$.

Multiplying gives $1 = 1 \times 1 = i \times i = -1$.

So, $1 = -1$?

I don't understand what is wrong. Can someone help?