one to one function 2nd way

1. 1
   Take the function you want to check. For example, you might want to check f(x) = x-3 / x+2.
2. 2
   Plot the function on the x-y plane. Calculate some values for a few numbers, both positive and negative, using the function. Plot them on paper or using mathematics software. You will see an estimated shape of the function.
3. 3
   Draw a horizontal line on the graph. Make a horizontal line anywhere on the graph. This will allow you to perform the "horizontal line test."
4. Edit step
   4
   Determine whether the line intersects the graph of the function at more than one point. If the horizontal line intersects the graph at only one point, the function is one to one. If the horizontal line intersects the graph in more than one point, the function is not one to one.

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