# Mathematics & Logic

Personal and Historical Perspectives of Hans Bethe. Pandigital Approximations. Courses & Video Lectures. Fractals. LiveMath™ Software Products. An Intuitive Explanation of Fourier Theory. Steven Lehar slehar@cns.bu.edu Fourier theory is pretty complicated mathematically.

But there are some beautifully simple holistic concepts behind Fourier theory which are relatively easy to explain intuitively. There are other sites on the web that can give you the mathematical formulation of the Fourier transform. Fast and usable calculator. Octave. GNU Octave is a high-level interpreted language, primarily intended for numerical computations.

It provides capabilities for the numerical solution of linear and nonlinear problems, and for performing other numerical experiments. It also provides extensive graphics capabilities for data visualization and manipulation. Sin & Cos: The Programmer's Pals! 9 Mental Math Tricks. Math can be terrifying for many people.

This list will hopefully improve your general knowledge of mathematical tricks and your speed when you need to do math in your head. 1. Multiplying by 9, or 99, or 999 Multiplying by 9 is really multiplying by 10-1. Impress your friends with mental Math tricks » Fun Math Blog. See Math tricks on video at the Wild About Math!

Mathcasts page. Being able to perform arithmetic quickly and mentally can greatly boost your self-esteem, especially if you don't consider yourself to be very good at Math. And, getting comfortable with arithmetic might just motivate you to dive deeper into other things mathematical. This article presents nine ideas that will hopefully get you to look at arithmetic as a game, one in which you can see patterns among numbers and pick then apply the right trick to quickly doing the calculation.

Uncoiling the spiral: Maths and hallucinations. December 2009 You can read a more accessible version of this article here.

Think drug-induced hallucinations, and the whirly, spirally, tunnel-vision-like patterns of psychedelic imagery immediately spring to mind. But it's not just hallucinogenic drugs like LSD, cannabis or mescaline that conjure up these geometric structures. People have reported seeing them in near-death experiences, as a result of disorders like epilepsy and schizophrenia, following sensory deprivation, or even just after applying pressure to the eyeballs. Science Mysteries, Fibonacci Numbers and Golden section in Nature. Golden Ratio & Golden Section : : Golden Rectangle : : Golden Spiral Golden Ratio & Golden Section In mathematics and the arts, two quantities are in the golden ratio if the ratio between the sum of those quantities and the larger one is the same as the ratio between the larger one and the smaller.

Expressed algebraically: The golden ratio is often denoted by the Greek letter phi (Φ or φ).