How to interpret this Calc trendline equation?

Version: 7.0.3.1
Build ID: d7547858d014d4cf69878db179d326fc3483e082
CPU threads: 6; OS: Linux 4.15; UI render: default; VCL: gtk3
Locale: en-US (en_US.UTF-8); UI: en-US

The trendline equation is `f(x) = 123,456.789 exp(0.12345x)`. I tried the calc function `=123456.789*EXP(0.12345*B2)` (where `B2` has the number of data points along the X axis, but the answer is off by a factor of 10^6.

Where do you see the discrepancy?

`f(x) = 123,456.789 exp(0.12345x)` is the same thing as `f(x) = 123456.789 exp(0.12345x)` and in turn this is `=123456.789*EXP(0.12345*B2)` since obviously your locale (`English (US)`?) uses a `,` (comma) as thousands separator and a `.` (decimal point) as decimal delimiter.

@anon73440385 the trendline equation finishes just above one million, whereas `=123456.789*EXP(0.12345*B2)` returns 1 trillion.

You wrote: The trendline equation is f(x) = 123,456.789 exp(0.12345x). Let’s take that serious and caluculate the value for `x=129.00`, which is `f(129.00) = 123,456.789 exp(0.12345*129.00)` and this is: `1,017,832,505,066.09` which is exactly the same thing as your screenshot shows for `=123456.789*EXP(0.12345*B2)`. A trendline is called a trendline because it allows to calculate values outside the real range of existing data, which the equation is derived from (You did not provide the data, from which your trendline is derived, so I need to take it given). Hence I don’t understand, why you use the phrase the trendline equation finishes just above one million. The trendline function `a*exp(b*x)` is defined for all x ∈ ℝ (set of real numbers) and does not end anywhere.

@anon73440385 My chart has 129 x-values, but only 36 y-axis values. Thus, the trendline continues far beyond the 36 y-axis data points, showing me what the value “will” be for the 129th x-value, based on the equation `f(x) = 123,456.789 exp(0.12345x)`.

@anon73440385 PEBKAC. When I tried the (real) formula again, it worked perfectly.

Show your sample file. I can’t explain anything else I did, esp. I can’t comment anything related to how you got the trendline and whether is make sense at all to use Regression Type `Exponential` - You did not provide the data. So I take the trendline function as given.

> My chart has 129 x-values, but only 36 y-axis values

Makes no sense at all to me.