Microsoft Office Tutorials and References
In Depth Information
Figuring Out Other Roots and Powers
Figuring Out Other Roots and Powers
The SQRT function is provided because some math people expect it to be there.
There are no equivalent functions to figure out other roots.
If you multiply 5 × 5 × 5 to get 125, then the third root of 125 is 5. The fourth
root of 625 is 5. Even a $30 calculator offers a key to generate various
roots beyond a square root. Excel does not offer a cube root function. In
reality, even the POWER and the SQRT functions are not necessary.
=6^3 is 6 raised to the third power, which is 6 × 6 × 6, or 216.
=2^8 is 2 to the eighth power, which is 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2, or 256.
For roots, you can raise a number to a fractional power:
=256^(1/8) is the eighth root of 256. This is 2.
=125^(1/3) is the third root of 125. This is 5.
see Chapter8 , UnderstandingFormu-
las .
Thus, instead of using =SQRT(25), you could just as easily use =25^(1/2).
However, people reading your worksheets are more likely to understand
=SQRT(25) than =25^(1/2).
See Chapter15 , UsingTrig,Matrix,andEngineeringFunctions ,
to read more about theSQRT andSQRTPI functions.
Using SIGN
to Determine the Sign of a Number
Although the SIGN function belongs with the information functions, Mi-
crosoft groups it with the math functions. You can see it used in the MROUND
function example shown previously in this chapter to prevent an error. Sim-
ply, =SIGN(number) reports whether numberis negative, zero, or positive.
SIGN to Determine the Sign of a Number
SIGN determines the sign of a number. It returns 1 if the number is positive, 0 if
the number is 0, and 1 if the number is negative. The argument numberis any
real number.
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