A new continued fraction for pi

I love continued fractions. The golden ratio: The square root of 2: The base of the natural logarithm: Pi: In the most recent American Mathematical Monthly (December 2008) Thomas J. Pickett and Ann Coleman, in their note “Another Continued Fraction for ,” present the following beautiful continued fraction in which the terms down the diagonal…

Four color theorem applets

The four color theorem is a beloved result with a long and fascinating history. The theorem says that four colors suffice to color any map so that no two bordering regions are the same color. The conjecture was made in 1852 by Francis Guthrie. After many, many failed proofs, the conjecture was finally put to…