Function calculateSum

calculateSum(f, b, a?, epsilon?, iterations?): Decimal
Calculates the sum of f(n) from a to b using either the trapezoidal rule or a basic loop depending on the size of b - a.
Parameters
- f: ((n: Decimal) => Decimal)
  The function f(n) to calculate the sum.
  - - (n): Decimal
    - Parameters
      n: Decimal
      Returns Decimal
- b: DecimalSource
  The upper limit for the sum.
- a: DecimalSource = 0
  The lower limit for the sum. Defaults to 0. The order is reversed because a is optional. Deal with it.
- Optionalepsilon: DecimalSource
  The maximum error tolerance, geometrically. Defaults to DEFAULT_TOLERANCE. Only used if b - a is less than or equal to DEFAULT_ITERATIONS.
- Optionaliterations: number
  The amount of iterations to perform. Defaults to DEFAULT_ITERATIONS. Only used if b - a is greater than DEFAULT_ITERATIONS.
Returns Decimal
- The calculated sum of f(n), as a Decimal.
Example
```
const f = (x) => x.pow(2);
const sum = calculateSum(f, 10);
console.log(sum); // ~385
```
- Defined in classes/numericalAnalysis/sum.ts:162