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Math Help - Need a function that is near 1 at high values and tends to zero at low values

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    Newbie xlxc34's Avatar
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    Need a function that is near 1 at high values and tends to zero at low values

    I've got a very simple problem that I can't seem to figure out. I need a function that is near 1 at high values of x but tends to zero as it gets nearer to 0. My first thought was f(x)=1-1/x, but it doesn't have enough control. For example, I need it to have a value of about 1 at x=1e8, still 1 at x=2e7 but at say x=5e5 it needs to have a value of 0.0000001. These numbers have kind of been plucked out of the air, I'm just trying to illustrate that I need a bit more control than I can achieve with 1-1/x.

    Any help will be much appreciated!

    Pete
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    Re: Need a function that is near 1 at high values and tends to zero at low values

    y = 1 - e^{-x}
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    Re: Need a function that is near 1 at high values and tends to zero at low values

    Quote Originally Posted by xlxc34 View Post
    I've got a very simple problem that I can't seem to figure out. I need a function that is near 1 at high values of x but tends to zero as it gets nearer to 0. My first thought was f(x)=1-1/x, but it doesn't have enough control. For example, I need it to have a value of about 1 at x=1e8, still 1 at x=2e7 but at say x=5e5 it needs to have a value of 0.0000001. These numbers have kind of been plucked out of the air, I'm just trying to illustrate that I need a bit more control than I can achieve with 1-1/x.
    Look at 1-e^{-x},
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