simple: what does -i^2 generally equal?

[Guest]

ok, there's a mis-understanding between a friend and myself. does -i^2 equal +1 or
-1?

 

[Gene]

i=sqrt(-1) so i²=-1
-i²=-(-1)=1

 

[stapel]

Depends what you mean. Are you saying "-(i²)" or "(-i)²"? That is, are you including the "minus" sign in the squaring, or not?

Thank you.

Eliz.

 

[TchrQbic]

ok, there's a mis-understanding between a friend and myself. does -i^2 equal +1 or
-1?

As written, with no parentheses, the negative is not affected by the exponent. Thus - 1² = - 1.

 

[ChaoticLlama]

If you meant to write this
\(\displaystyle [- (i)^2]\)

Then it is equal too
\(\displaystyle - (\sqrt { - 1} )^2 = - ( - 1) = 1\)

If you meant to write this
\(\displaystyle ( - i)^2\)

Then it is equal to
\(\displaystyle ( - \sqrt { - 1} )^2 = ( - 1) = - 1\)

Please use brackets next time.