square of negative number on calculator-wrong

• Sep 10th 2011, 10:38 PM
celtic1234
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

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

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

thanks
John
• Sep 10th 2011, 10:48 PM
Prove It
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

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

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 $\displaystyle -2^2$.

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

What you are wanting is $\displaystyle (-2)^2$, so you need to enter it like this.
• Sep 10th 2011, 10:54 PM
celtic1234
Re: square of negative number on calculator-wrong
thanks-this forum is great!!