What is (√-1)²?

2 Answers
Oct 21, 2017

-1

Explanation:

#sqrt(-1) = i#

#(sqrt(-1))^2= i^2=i*i= sqrt(-1)*sqrt(-1)= -1#

Oct 21, 2017

#(sqrt(-1))^2 = -1#

Explanation:

By definition a square root of a number #x# is a number #y# such that #y^2 = x#.

#sqrt(-1)# denotes the principal square root of #-1# which is a square root of #-1#.

Therefore its square must be #-1#.