Section 3

# Functions

You have already learned to use the arithmetic functions (+, , ×, ÷) in both the stack and the addressable registers. You have also learned to move numbers among the calculators registers and to enter and display data in both fixed and scientific format. To complete the subject of manual calculation, we will return to the non-arithmetic functions, things like sine, logarithm, square root ...
Keys Introduced in this Section
 ABS D.MS INT n! R P 1/x COS D.MS+ LN OCT SIN DEG GRD LOG RAD TAN yX
Taken as a whole, the functions are both powerful and important. While, conceivably, you might not use them directly, you will almost surely use them indirectly when you use preprogrammed cards from the Standard Pac and other pacs. For example, you already used the exponential function (yX) and the integer function (INT), when you used the Personal Investment program presented in the Introduction. Without yX, the program would have to use more laborious arithmetic methods, repeatedly.
The functions are both easy to learn and easy to use. In the Introduction you found that to do a function, you press a prefix key (f, f-1, or g) and follow it by the desired function key: you use the g prefix to calculate a function having a blue symbol, you use f to calculate a function having a gold symbol, and you use f-1 to calculate, the inverse or complements of the function denoted by a gold symbol.
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