Common Algebra Mistakes
Example: Function Notation 
The Goal
Compute f(g(4)) if f(4) = 4, g(4) = 2 and f(2) = 1. The Mistake
Find the algebra mistake: (Roll the mouse over the algebra to see a hint in red) The Correction
(Roll the mouse over the area above to see the correction in blue) An Explanation The expression f(g(4)) does not indicate the product of two function values. In other words, it is not equal to f(4) times g(4). Instead, f(g(4)) means to compute g(4) and plug the result into the function f(x). In this case g(4) = 2, so f(g(4)) = f(2) = 1. This is an example of function composition. 
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