Psion Teklogix 32M/64M, netBook Displaying numbers, Factorials, Logarithms, Exponent notation

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

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 ex, then enter the value you want to find e to the power of. Press =.

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

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.

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