My son read this page of Short Cuts: Maths yesterday. This evening I asked him why can’t you? He said “if you ask a mathematician what’s the square root of 4, they’ll say plus 2 or minus 2.” He was a little unclear on why -2 times -2 is 4.
Then he looked thoughtful and said “what’s the square root of minus 4?”
I said “Ah, that’s a good question”. He giggled and said “I know, it’s i 4. I read about it in an earlier chapter.”
I told him that it’s 4i, but you don’t learn that until university. He was extremely chuffed.
