Given: 1 = 1, since that's obvious
1 = √1 1 = √(-1 × -1) 1 = √(-1) × √(-1) 1 = i × i 1 = i2 1 = -1
Q.E.D.
Answer (highlight):
| Remember, square root gives TWO answers. Certain rules have to be followed when you break up the radical like that. This is an example of how NOT to do it. |