Hi, I cannot find any other reference to this formula: sin(x)/cos(x-1) it seems to fit with Euler's identity as given by Wikipedia. Euler's identity is a special case of this identity equation. I've actually posted this on the Wikipedia page to see if I can get confirmation of this or have someone tear it down. It also has some bizarre properties between -∏-3 ≤ x ≤ ∏-3. More information on this function from wolframalpha.com My maths is very rusty and originally derived the formula as I thought it would make a pretty graph which I think it does. Only since reading up on prime numbers did I revisit this and check for values less than 1. I'm startled at how simple looking the function is, yet unable to find it in this form anywhere. I'd be interested to hear any opinions on it and will do my best to answer any questions about it. Thanks!