Calculate y-values in chart?

[perolav]

Hi,
I have a set of data, 100 x-values with corresponding y-values. Only about every third of the y's have a value, but by letting excel interpolate the graph, I can see how the graph should look like.

My questions are:
1. Can excel give me the formula to the graph it has drawn? Something like: "Show Equation"?

2. Is there a way to find out the y-value to a corresponding x-value? The graph has no standard-form, ie. it's not a parabel, so I don't know if I can use "trend" or "forecast"? The form of the graph is highly irregular, but excel managed to draw the graph, so it must know all it's y-values?

Please ask if anything is badly explained.

Thanks, perolav

[Bill Martin -- (Remove NOSPAM from address)]

perolav wrote:
> Hi,
> I have a set of data, 100 x-values with corresponding y-values. Only
> about every third of the y's have a value, but by letting excel
> interpolate the graph, I can see how the graph should look like.
>
> My questions are:
> 1. Can excel give me the formula to the graph it has drawn? Something
> like: "Show Equation"?
>
> 2. Is there a way to find out the y-value to a corresponding x-value?
> The graph has no standard-form, ie. it's not a parabel, so I don't know
> if I can use "trend" or "forecast"? The form of the graph is highly
> irregular, but excel managed to draw the graph, so it must know all
> it's y-values?
>
> Please ask if anything is badly explained.
>
> Thanks, perolav
>
>


You apparently found how to tell the chart to draw a trend-line for you. On
that same panel where you tell it what form of equation to fit to the data
there's a tab at the top labeled "options". Click that and you can select
"Display equation on chart". From that you should be able to calculate the Y
values you want.

Bill