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Math Help - square of negative number on calculator-wrong

  1. #1
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    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)

    The actual answer is 4?

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

    thanks
    John
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  2. #2
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    Re: square of negative number on calculator-wrong

    Quote Originally Posted by celtic1234 View Post
    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)

    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 -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.
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    Re: square of negative number on calculator-wrong

    thanks-this forum is great!!
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