Very substantial four-page article on how the block & tackle works. (It's a simple machine -- a pulley.) Lots of illustration. Mechanical advantage, formulae, solved problems, all here. Good source for info.

Very substantial four-page article on how the block & tackle works. (It's a simple machine -- a pulley.) Lots of illustration. Mechanical advantage, formulae, solved problems, all here. Good source for info.

Very substantial four-page article on how the block & tackle works. (It's a simple machine -- a pulley.) Lots of illustration. Mechanical advantage, formulae, solved problems, all here. Good source for info.

An excellent, detailed tutorial explaining trigonometric substitution. Includes formulas, equations and examples.

This site from ScienceWorld provides a brief two sentence overview of Abraham DeMoivre's life and his famous formulas. Links are provided to view both the Stirling's formula, as well as the Gaussian integral.