square of negative number on calculator-wrong

Hi

this may seem like a silly question but anyway...

Why is it when i calculate the square of a negative number on my calculator that i get the wrong answer;

My calculator gives the following answer

$\displaystyle x^2 = -4 (when x=-2) $

The actual answer is 4?

I end up just typing in -2 x -2 instead-am i missing something?

thanks

John

Re: square of negative number on calculator-wrong

Quote:

Originally Posted by

**celtic1234** Hi

this may seem like a silly question but anyway...

Why is it when i calculate the square of a negative number on my calculator that i get the wrong answer;

My calculator gives the following answer

$\displaystyle x^2 = -4 (when x=-2) $

The actual answer is 4?

I end up just typing in -2 x -2 instead-am i missing something?

thanks

John

It's because of how you're entering it into the calculator. I expect you are typing $\displaystyle \displaystyle -2^2$.

The calculator reads this as $\displaystyle \displaystyle -\left(2^2\right) = -4$ since it performs exponentiation before negation (multiplication).

What you are wanting is $\displaystyle \displaystyle (-2)^2$, so you need to enter it like this.

Re: square of negative number on calculator-wrong

thanks-this forum is great!!