User talk:23.238.128.118

Dear sir, you have very good collection of trigonometric identities. But you don't have identities for sin(nx), cos(nx) and tan(nx). For example tan(5x)=tan(x-72)tan(x-36)tan(x)tan(x+36)tan(x+72) not mentioned. My email is motahed1@yahoo.com (sorry for mistake motahed1@qq.com). Sincerely Omid Motahed