negative number raised to even power

[DrD]

It seems technology and opinions differ on definitions for this case. I can't remember any of my math educators ever saying that -2 squared is -4. Perhaps they did when I was snoozing; not that I ever did that during class time!

I have several calculators, most are safely stored away without batteries, and so I can't readily verify which displays what. A few TI calcs, and my hp50g agree with the way I learned, though, that -2^2 = 4.

The Prime, and Wolfram Alpha both recognize that -2^2 are really two separate operations: negating 2, and raising to the even power. Consequently, the rules of hierarchy would have you to take the power first, and then negate the result, thus negative results for negative numbers, raised to even powers. If "they" say it, it must be so!

I just encountered this situation while working with a program, and even though this has been discussed before, I hope it's worthwhile to mention, "don't forget to enclose negative numbers in parentheses when raising to even powers!" You might get diminishing returns, otherwise!

-Dale-