Question

What does the symbol for factorial function (n!) mean?

a.
It means to divide a series of descending natural numbers.
c.
It means to divide a series of ascending natural numbers.
b.
It means to multiply a series of descending natural numbers.
d.
It means to multiply a series of ascending natural numbers.

Answer 1

It means B and it can also mean D.

Take for example
`3!` which can be written as
`3!=3\cdot2\cdot1` in descending order however
`3\cdot2\cdot1=1\cdot2\cdot3=3!`.

Further reading.

The factorial function
`n!` where
`n\in\mathbb{Z}^+` is defined as taking the n-th derivative of exponential function
`x^n` namely,

`(d^n)/(dx^n)x^n=n!`.

We observe that we approach smaller and smaller values of n and therefore multiply by smaller and smaller natural number while total product increasing since every number we multiply the product with is non-decimal.

Hope this helps.

Answer 2

B. It means to divide a series of ascending natural numbers.

Explanation:

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