Psion netBook, User Manual

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124 Calc
Factorials Factorials Factorials Factorials Factorials
The x! button in the Scientific view calculates the factorial of a
number. A factorial is the result of multiplying all the numbers
from a given starting number down to one. So, the factorial of 4
(written as 4!) is 4×3×2×1=24.
Note: You can use factorials to find the number of ways things
can be arranged. For example, if you want to find possible
anagrams of a word with four letters, 4! shows that there are 24
ways these letters can be arranged.
•
To find the factorial of a number: enter the number of
which you want to find the factorial. Tap x! and tap = .
Logarithms Logarithms Logarithms Logarithms Logarithms
You can use the Scientific calculator to calculate logs and natural
logs.
• To calculate the log (base 10) of a number: tap log ,
then enter the number. Press = .
• To calculate the natural log (base e) of a number: tap
ln , then enter the number. Press = .
•
To calculate e to a given power: tap e
x
, then enter the
value you want to find e to the power of. Press = .
Displaying numbers Displaying numbers Displaying numbers Displaying numbers Displaying numbers
The Scientific calculator can display numbers in the following
formats:
• Normal: this is adequate for most calculations. Numbers are
displayed in standard notation to 12 significant figures, with
decimal places and an exponent as required.
• Fixed: this format always displays results with a specified
number of decimal places, e.g. for currency calculations.
• Scientific: you may find this useful for dealing with very large
or very small numbers. Numbers are displayed as a single
digit to the left of the decimal point, a specified number of
significant figures, and then an exponent.
To change the number format: select the command from the
Tools menu. If you choose Fixed or Scientific, you can set the
number of decimal places or significant figures to be displayed.
Exponent notation Exponent notation Exponent notation Exponent notation Exponent notation
You can express very large and very small numbers more
succinctly using positive and negative exponents. For example,
57 200 000 can be expressed as 5.72E7.
To express a number as an exponent:
1. Enter the first part of the number, normally as a decimal
fraction.
2. Tap exp . An ‘
E
’ will appear on the calculation line. To
express a very small number, tap +/- to insert a minus sign
before the second number.
3. Enter the number of decimal places that the first number
needs to be moved to the left.