[MOVED] Graph of f(x): evaluating function at given point

Jade

Junior Member
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Sep 16, 2006
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I have a graph of f(x). Then the question is f(5)? How do you express this? In interval notation? I would love to insert the graph to become more clear, but do not see this option. There are 7 points on the graph - (-4, 1.2), (-3, 4.5), (-2, 0), (-.4, -2.3), (0, -2.25), (3, 0) and finally (5, -3.5). All the points are solid except for the last one.
 
Are you sure the question is f(5) and not f '(5)? If the point (5, -3.5) is not solid and it's a clear circle that means f(5) does not exist. But f '(5) does exist, since that's the behavior of f(x) as x approaches the point x = 5.
 
It is f(5)

Does that mean f(5) is undefined in the graph. And just to recap - when a point on a graph is not solid (empty) - it means that it does not exist?

So with the previous points for the graph what would f(-3) be? How would it be written? In interval notation?
 
Jade said:
what would f(-3) be? How would it be written? In interval notation?
How could a function value be written in interval notation...?

Are you not familiar with functions or function notation?

Eliz.
 
This is all new to me, but

we are graphing functions as well which makes me want to find the interval notation. I think I am confusing myself between graphing a function and function whatever = what on a graph.

I have the function f(5) and I have the graph.

So the questions is on the graph f(5) =

I have previously given the points, but one line seems to say f(x) which is line (-3, 4.5) and (-2, 0) - Would this be the function or is the whole graph the function.
 
I think you might be a little confused.
interval notation is a set of values on a graph, not just one value.

When you say f(5), that means the value of y when x =5. the actual function is called f(x).

f(-3) would be 4.5, since that's the value of y when x = -3. and yes, if the circle is clear and not solid, that means it's undefined.

And since i'm not able to see the actual graph...is there only one line on the graph? if there is the whole graph is is f(x). sometimes, though, even if there's multiple lines on a graph, the whole thing could still be f(x). if there are no other graph names, such as g(x) or t(x) (for example), then the whole graph is probably f(x).
 
f(x)

:p You have been a great help - I have studied all day and I think I am getting the hang of it.
 
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