The SERIESSUM function in Google Sheets is **useful when you need to compute the sum of a power series.**

Wee can use a power series to approximate various mathematical constants and functions. However, this function is mostly used in the context of user-defined models.

##### Table of Contents

The rules for using the `SERIESSUM`

function in Google Sheets are as follows:

- The function requires four arguments that determine the values to input in the power series.
- The function then outputs a number which is the sum of every element in the indicated power series.

Let’s take a look at a quick demonstration of this function in use.

Let’s say we would like to approximate the value of Pi/4 radians using a power series. We know that each term has the following coefficients (1, -0.5, 0.04167, -0.0001389) and a constant of pi/4 (0.78539…). The first term is raised to the power of 0, and each term increments that power by 2. How do we determine the value of this power series?

With the `SERIESSUM`

function, it becomes quite easy to solve this without having to type the entire formula yourself, which might become a tedious process for the user.

This use case is just one of many ways to use the `SERIESSUM`

function in Google Sheets.

Let’s learn how to write the `SERIESSUM`

function ourselves in Google Sheets and later test out the function with actual date values.

**The Anatomy of the SERIESSUM Function**

The syntax of the `SERIESSUM`

function is as follows:

=SERIESSUM(x, n, m, a)

Let’s dissect this thing and understand what each of these terms means:

**=**the equal sign is how we start any function in Google Sheets.**SERIESSUM()**is our`SERIESSUM`

function. It computes the sum of a power series.**x**refers to the input to the power series.**n**refers to initial power to which x must be raised.**m**refers to the additive increment.**a**refers to the values of the coefficients of the power series. It may be in the form of an array or a cell range.

**A Real Example of Using SERIESSUM Function**

Let’s have a look at an example of the `SERIESSUM`

function being used in a Google Sheets spreadsheet.

In the table below, we have our four arguments laid out on a table. Using the `SERIESSUM`

function, we were able to come up with 12 as a result.

To get the value in cell **B7**, we just need to type in the following formula:

=SERIESSUM(B2,B3,B4,B5:D5)

Let’s confirm whether this is the right answer.

In the worksheet below, we go step-by-step into how to compute the sum of the power series. Since there are three coefficients, we’ll be having three terms. Each term has a corresponding coefficient (shown in parentheses) and a constant raised to some power. The power is indicated by the argument **n** and grows for every succeeding term by **m. **Since n=1 and m=0, the power remains 1 for every term.

Computing for the final answer gives us 2+4+6=12 as the final simplified equation.

In the example below, we have a different set of arguments. Manually computing for the series shows that `SERIESSUM`

has produced the right result.

You can generate your own copy of the spreadsheet above using the link attached below.

Let’s start writing `SERIESSUM`

function in Google Sheets. Head over to the next section to begin our step-by-step guide on how to use the function.

**How to Use SERIESSUM Function in Google Sheets**

- First, we must set up the arguments for our
`SERIESSUM`

function. As seen below, we must have values for n, m, x, and a.

- To start using the
`SERIESSUM`

function, select the cell we will first put our function’s output. In this example, we’ll place our final result in cell**G7**.

- Next, we just simply type the equal sign ‘
**=**‘ to begin the function, followed by ‘**SERIESSUM(**‘. - You may encounter a tooltip box with information about the
`SERIESSUM`

function. This box can be minimized by clicking on the arrow in the top-right-hand side.

- Next, we need to type in our arguments. In this case, our arguments are already placed in the proper order. We should write the last argument as a range.

Afterward, simply hit**Enter**on your keyboard to let the function evaluate.

**Frequently Asked Questions (FAQ)**

**Why does my formula return a #VALUE! error?**

The`SERIESSUM`

function only accepts numeric values. Non-numeric values will result in a #VALUE! error.**How many terms can be in my power series?**

The number of terms in your power series is determined by the size of your coefficient array. If your array has a length of 20, then your power series will likewise have 20 terms.

That’s everything you need to know about the `SERIESSUM`

function in Google Sheets. This step-by-step guide shows how easy it is to set up your own power series for your own custom models.

You may now use the `SERIESSUM`

function in Google Sheets together with the various other Google Sheets formulas available to build powerful spreadsheet solutions.

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