Ochlophobia Ochlophobia Ochlophobia ("Fear of Crowds") and demophobia ("Fear of Unruly Mobs") are terms for types of social phobia or social anxiety disorder whose sufferers have a fear of crowds. Sufferers may offer various rationalizations of the phobia, such as the fear being trampled in a crowd, getting a deadly disease from people within the crowd, getting lost in the crowd, or feeling insignificant when surrounded by a crowd. People who are shy and introverted are most likely to experience ochlophobia, but not all introverts have anxiety problems. Ochlophobic people are often unable to handle situations involving parties, going to theaters,
Proof that π is irrational In 1761, Lambert proved that is irrational by first showing that this continued fraction expansion holds: Then Lambert proved that if "x" is non-zero and rational then this expression must be irrational. Since tan(/4) = 1, it follows that /4 is irrational and therefore that is irrational. A simplification of Lambert's proof is given below. This proof uses the characterization of as the smallest positive number whose half is a zero of the cosine function and it actually proves that is irrational. As in many proofs of irrationality, the argument proceeds by reductio ad absurdum. Consider the sequences ("A") and