This site sums up the trigonometric identities of tangent, cotangent, secant, and cosecant in the terms of since and cosine. This site mentions all the identities that should be memorized. The site shows a number of trigonometric functions such as Pythagorean formula for sines and cosines, identities for negative functions, sum formulas for sine and cosine, and double angle formulas for sine and cosine. This site also mentions the less important identities that are related to the identities mentioned before. These less important identities are Pythagorean formula for tangents and secants, difference formulas for sine and cosine, and half-angle formulas. This site even mentions the formulas that they feel are least important to remember. These obscure identities are product-sum, triple-angle and half-angle,
             I think this site is very useful for a trig student in any level of mathematics. The site is very clear and easy to understand. All the identities are listed with titles and some are even listed with explanation. One characteristic of the site that I don't like is that it doesn't illustrate any links to other trig sites that might become helpful in other aspects of trigonometry. For the most part, the site is well put together and shows all the identity formulas evenly spaced apart, which makes it easy to understand.
             I would support that mathematics and writing are related. One needs to use writing in order to solve some of math's basic operations; to some of math's most complicated.
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