Remember we calculated the sum of first N consecutive natural number at http://www.exposix.com/members/answers/How-to-calculate-Sum-of-first-n-Natural-numbers.html ?
Many of my friends ask me the trick to remember the formulae for sin 3x and cos 3x so that they can reproduce the same in a close book exam to score high. Every time they ask me I tell them to derive
I've seen many people don't understand trigonometry and can't remember simple standard values for sin, cos and tan. So, I came up with a simple solution/ trick through which you can calculate standard