This means that global assignments can be defined anywhere in the worksheet and still be recognized. All global assignment definitions in the worksheet are scanned by PTC Mathcad prior to scanning for normal assignment definitions. The global definition operator (≡) CTRL + TILDA ∼ or CTRL+SHIFT+ACCENT is used to assign a global variable. It will be discussed in more detail in future chapters. It is also used for programming, solving, and in symbolic equations. The Boolean equal to operator ( =) CTRL+EQUAL SIGN is used to evaluate the equality condition in a Boolean statement. The evaluation operator (=) EQUAL SIGN is used to evaluate a variable, function, or expression numerically. The definition operator (:=) COLON is used to define variables, functions, or expressions. It is important to understand the difference between them. There are four equal signs used in PTC Mathcad. It does not retain a number in memory with a higher level of precision. The level of precision specified is the number that PTC Mathcad uses for all future calculations.
It is important to understand that the level of precision is very different than specifying the number of decimal places you want displayed in numeric calculations. You can control the level of precision by typing a comma following the “float” keyword and typing an integer, which defines the desired precision. When using floating-point calculations, PTC Mathcad uses a default level of precision equal to 20. This is accomplished by using the keyword “float.” Using the “float” keyword skips the display of symbolic results. There is another way to have the symbolic processor return numeric results. In previous examples, we have shown how PTC Mathcad provides a floating-point result by including a decimal in an expression, or by including the evaluation operator in the definition of a variable, prior to using the symbolic evaluation operator.
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