• sp3ctr4l@lemmy.zipEnglish
    01·
    2 months ago

    No, PEMDAS.

    You do the exponent first, then multiplication.

    -3² = -1 * 3²

    or

    -3² = (-1)(3²)

    (-3)² would be how you’d represent what you are interpreting it as.

    Your interpretation:

    -3² != (-3)² = (-1(3))² = (-1 * 3)² = 9

    vs

    Correct Interpretation:

    -3² = -3² = (-1)(3²) = -1 * 3² = -9

    EDIT:

    Every time you see a - directly infront of a number, say…

    -x

    …and there is no space to indicate the - represents a subtraction operator, such as in…

    y - x

    …the immediate prefix - actually represents:

    (-1)x

    or

    -1 * x

    Due to PEMDAS, if the exponent ² or ^2 is attached to…

    -x² or -x^2

    … this actually represents

    (-1)(x²) or -1 * x^2

    … such that PEMDAS is upheld, and the exponent recieves computational primacy.

    EDIT 2:

    I don’t make these rules, but this is how it works.

    Double check in wolfram alpha if you doubt it.

    • 💡𝚂𝗆𝖺𝗋𝗍𝗆𝖺𝗇 𝙰𝗉𝗉𝗌📱@programming.devEnglish
      11·
      3 days ago

      You do the exponent first, then multiplication.

      -3² = -1 * 3²

      There’s no multiplication, just subtraction (from an unwritten 0). -3² = 0-3²

      there is no space to indicate the - represents a subtraction operator

      Spaces don’t mean anything in Maths, and I don’t know why people keep adding them in! A minus sign is a minus sign, whether there are spaces next to it or not.

      the immediate prefix - actually represents: (-1)x

      No, it actually doesn’t. It represents 0-x. Every operation on the number line starts from 0.

      this actually represents (-1)(x²)

      No, it actually represents 0-x²

      such that PEMDAS is upheld

      Which what you wrote doesn’t. M refers literally to Multiplication signs. S refers literally to subtraction signs. -x² is E then S in PEMDAS.

      I don’t make these rules

      You did make those up actually (or you’ve repeated someone else who made them up).

      but this is how it works

      No it isn’t. A minus sign is the S in PEMDAS, not M.

      Double check in wolfram alpha if you doubt it

      Look in a Maths textbook. Wolfram is known to be wrong in several areas. University professors warn their students against using it without adding brackets everywhere.