Microsoft Office Tutorials and References

In Depth Information

**FACT**

Figure 10.13

The
EXP
function

returns the e raised

to the power of the

number.

FAC
The
FACT
function returns the factorial of a number. The factorial of a number is equal to the

product of integers from 1 to number.

=FACT(number)

The
NUMBER
argument is the non-negative number you want the factorial of. If number is not

an integer, it is truncated (see the
TRUNC
function later in this chapter).

Example:
FACT(4)
equals 24, which is equivalent to
=1*2*3*4
.

You also might want to calculate the sum of a series of factorials from n to m, where n and m

are positive integers. You can do this with a formula such as
=FACT(n)+FACT(n+1)..+FACT(m)

but the formula might get a little long. Instead, you can use an array formula to perform this

task. This formula is of the form
=SUM(FACT(ROW(n:m)))
. As an example, the formula

=SUM(FACT(ROW(2:5)))
returns 152, which is the sum of
FACT(2)
,
FACT(3)
,
FACT(4)
, and

FACT(5)
. Notice the example in Figure 10.14.

The use of the
ROW
function with a
RANGE
argument allows you to create an array of numbers. The

array created by the formula
ROW(1:10)
is an array of numbers from 1 to 10.

TIP

To use this formula you must remember that it must be entered as an array formula (by

holding down the Ctrl and Shift keys when pressing Enter).

Returns the factorial of a number. For example
1*2*3
….

NUMBER