<p>Let the function f be defined by f(x) = |x+1|
What is the least value of f?</p>
<p>A question like this is asking for the minimum y-value, correct? Is there an easy way to remember this or to know when it wants the x-value and when it wants the y-value?</p>
<p>Yes, it is asking for the minimum value of y.</p>
<p>The value of a function is the “output” of the function. Often the output is assigned to y, as in y=f(x), but it doesn’t have to be. (Just as x is often assigned to be the input of the function, but it doesn’t have to be that way either).</p>
<p>The question would either say y=f(x), and ask for the minimum y-value; or, it would just ask for the minimum value of the function. For the input side, it would ask for the least value in the domain of f, or it would say y=f(x), and ask for the least possible value of x.</p>
<p>Yes. f(x) typically equals y.</p>
<p>x= input, f(x)= output</p>
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<p>I remember you asking me a few physics related questions so think of x like t (time) on a displacement vs. time graph. No matter what the function is time will always be there. You can always plug in a value t. The minimum or maximum of the function is that x or t inserted in the function which yields an answer.</p>
<p>The only time a question will ask for the x value usually occurs when it explicitly says at what time value or at what x does the function have a minimum, maximum, or anything significant on the graph.</p>