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Thread: Function sign

  1. #1
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    Function sign

    What happens to a function when - is in front?

    -f(x)
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  2. #2
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    Nothing. The function remains the same.

    However, if we graph a new function, -f(x), we'll find that it's simply f(x) flipped across the x-axis.
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  3. #3
    No one in Particular VonNemo19's Avatar
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    you can visualize it like this

    $\displaystyle f(x)$ yields the coordinates $\displaystyle (x,y)$ and $\displaystyle -f(x)$ yeilds the coordinaes $\displaystyle (x,-y)$. So every $\displaystyle y$ value in the $\displaystyle f(x)$ is the mirror image of the $\displaystyle -f(x)$ outputs. That's why we say the $\displaystyle -f(x)$ is the reflection through the $\displaystyle x-axis$ of $\displaystyle f(x)$. Make sense?
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  4. #4
    MHF Contributor
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    Talking

    "f(x)" is just another name for "y". If you take a graph's y-values and change their signs, then you're moving the points to the opposite side of the x-axis. In other words, you're flipping the graph upside-down.
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