A question from an exam

[dasani123]

I recently had an exam where the last question was as follows:

-1 = i*i = sqrt(-1)*sqrt(-1) = sqrt(-1*-1) = sqrt(1) = 1

Does -1 = 1?

This was an engineering exam and was obviously just a gimme question, but i can't find any fault in the reasoning.

[MelchyBeau]

sqrt(1) = +/- 1, not just 1.

Melch

[lufbradolly]

-1 = sqrt(1) = 1

-1 doesnt equal 1 but the sqrt(1) can be either 1 or -1.