View source for Eval()vs.substitute()

The aim of this page is to demonstrate the difference between <code>eval()</code> and <code>substitute</code>.

Note:[[PGLabs]] is an efficient way to check code.

 $f = Compute(sqrt(3x + 1);
 $fx = $f->eval(x=>"3");
 displays 3.16228

The correct answer is a number.

 $f = Compute(sqrt(3x + 1);
 $fx = $f->eval(x=>"3");
 displays (3.16228)

The correct answer is a formula (hence the parenthesis)

One of the biggest differences between <code>eval()</code> and <code>substitute</code> is when they are used in conjunction with flags such as <code>reduceConstants</code> and <code>reduceConstantFunctions</code>,  which is described in more detail at:[[FormattingCorrectAnswers]]