# SERIESSUM

Given parameters `x`, `n`, `m`, and `a`, returns the power series sum a1xn + a2x(n+m) + ... + aix(n+(i-1)m), where i is the number of entries in range `a`.

### Sample Usage

`SERIESSUM(1,0,1,{FACT(0),FACT(1),FACT(2),FACT(3),FACT(4)})`

`SERIESSUM(A2,0,2,B2:B10)`

### Syntax

`SERIESSUM(x, n, m, a)`

• `x` - The input to the power series. Varies depending on the type of approximation, may be angle, exponent, or some other value.

• `n` - The initial power to which to raise `x` in the power series.

• `m` - The additive increment by which to increase `x`.

• `a` - The array or range containing the coefficients of the power series.

### Notes

• Power series may be used to approximate various constants and functions, including e (Euler's number), logarithms, integrals, trigonometric functions, etc. However, this function is usually used for custom user-defined models.

`SUMSQ`: Returns the sum of the squares of a series of numbers and/or cells.

`SUMIF`: Returns a conditional sum across a range.

`SUM`: Returns the sum of a series of numbers and/or cells.

`QUOTIENT`: Returns one number divided by another, without the remainder.

`PRODUCT`: Returns the result of multiplying a series of numbers together.

`MULTIPLY`: Returns the product of two numbers. Equivalent to the `*` operator.

`MINUS`: Returns the difference of two numbers. Equivalent to the `-` operator.

`DIVIDE`: Returns one number divided by another. Equivalent to the `/` operator.

`ADD`: Returns the sum of two numbers. Equivalent to the `+` operator.