Rationalization
 
By now I have taught easily a dozen freshman-level college math courses.  In every single one that I have taught I have faced the brainwashing that students have received to rationalize the denominator of a fraction.  (I use the word "brainwashing" here loosely.  Clearly I do not accuse any high school math instructor of actually using brainwashing techniques.)  For those that aren't aware or don't remember, a denominator is irrational when it has a square root (or any other root in it).  For example, 1/√ 2  has and irrational denominator.  The denominator can be rationalized by multiplying this fraction by 1 in the form of √ 2 /√ 2 , thus making it √ 2 /2.   The first thing that I find extremely ironic about this is that there are some fractions that simply cannot be rationalized.  This occurs when a transcendental number is in the denominator, such as π.  But, that aside, there is no mathematical reason for rationalizing the denominator.  T...