Symbolic calculations.You’ve seen Mathcad engaging in numeric calculations. This means that whenever you evaluate an expression, Mathcad returns one or more numbers, as shown at the top of Figure 14-1. When Mathcad engages in symbolic mathematics, however, the result of evaluating an expression is generally another expression, as shown in the bottom of Figure 14-1.
Figure 14-1: A numeric and symbolic evaluation of the same expression.
Example 1: Factoring and expanding expressions Enter an expression. Press the space bar until the entire expression is boxed. Select Symbolics - Expand or Symbolics - Factor to expand or factor the expression. Boxing (x 1).(x 4) and then selecting Symbolics - Expand yields: x2 5.x 4 Boxing x2 5.x 4 and then selecting Symbolics - Factor yields: (x 1).(x 4)
Example 2: Evaluating symbolic expressions Two method is illustrated below: 1) Using Symbolics - Evaluate - Symbolically from the main menu
and then selecting Symbolics - Evaluate - Symbolically yields:
Example 3: Simplyfing symbolic expressions Enter an expression. Press the space bar until the entire expression is boxed. Select Symbolics - Simplify.
Example 4: Solving symbolic equations using a SOLVE BLOCK There are two main differences from a regular Solve Block: 1) Do not use initial guesses. 2) Use the symbolic evaluation operator (right arrow) with the Find function.
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