yarliganfatih / rediscovery-of-math Goto Github PK

Isn't the factorial obtained by multiplying the numbers up to the start (0) of a number?

Positive numbers decrease to return to origin, negative numbers can increase to origin.

We can achieve this with a simple dynamic variable.
51ae5e1

const fact = (a) => {
    let ka = getCoefficient(a);
    if (remainder(a, 1) != 0) return undefined;
    if (a == 0) return ka;
    return mult(a, fact(subt(a, ka))); // In this way, negative numbers are multiplied by iteratively towards 0, too.
}

If we look at the results

• (-one)! = -1
• (-2)! = (-2)*(-1) = 2
• (-3)! = (-3)(-2)(-1) = -6
• (-4)! = (-4)(-3)(-2)*(-1) = 24
  ...
  As you can see, this was the handicap of negative numbers. Just like exponential numbers.