PRODUCT( ), FACT( ), POWER( ), and SQRT( ): Products, Factorials, Powers, and Square Roots

PRODUCT( ), FACT( ), POWER( ), and SQRT( ): Products, Factorials, Powers, and Square Roots

These four functions actually offer the same services provided by many of the simple operators covered in the last chapter, but, in some cases, they come with a few twists that may save you time.

The PRODUCT( ) function takes a list of numbers, multiplies them together, and gives the result. For example, the following formula multiplies 2*3*3, and arrives at 18:

 =PRODUCT(2,3,3)

One interesting characteristic of the PRODUCT( ) function is that in addition to accepting individual cell references, it also supports cell ranges. You can use PRODUCT( ) to multiply all the numbers in a range in the same way you use SUM( ) to add numbers. Here's an example:

 =PRODUCT(A2:A12)

You can use the FACT( ) function to calculate a factorial, which is a sequence of numbers (starting at 1), each of which is multiplied together to arrive at the result. For example, 5! (pronounced "five factorial") translates into 5*4*3*2*1, which works out to 120. Rather than typing in all these numbers and their accompanying multiplication symbols, you can use the following convenient formula:

 =FACT(5)

People use factorials in many areas of math, including probability theory and calculus. On the other hand, you aren't likely to find factorials cropping up in financial statements or expense reports.

POWER( ) is a straightforward function used for working with exponents. For example, if you want to calculate 4³, you can use one of two approaches. You can use the exponentiation operator:

 =4^3

or you can opt for the POWER( ) function:

 =POWER(4,3)

The POWER( ) function is useful if you frequently use cube rootsor any other exponential expressions whose exponent is a fractionbecause it lets you write clearer formulas. For example, imagine you want to find the cube root of 4, which, on paper, would be written as 4^1/3. Here's the operator-based expression for that:

 =4^(1/3)

With the POWER( ) function, you don't need to use the parentheses (and, more important, you have no chance of getting the wrong answer because you forgot to use them):

 =POWER(4,1/3)

If you simply want to calculate the square root of a number, you can use the POWER( ) function, or you can summon the SQRT( ) function, which requires only a single argument. Here's a sample formula that gives you 3:

 =SQRT(9)