Discover Questions

Tan2x=2tanx/1+tan^2x... my math teacher gave me this but I thought the double-angle identity was with a denominator 1-tan^2x? Could someone please solve this physics problem? Are there any flaws in the theory of Tensors? What is the science behind why black lights make light colors glow in the dark? A factory makes 250 tables a day. What is an equation that can be used to find the total number of tables made, y, after x days?