







Triple angle tangent formula 
20070315 

From sam: Hi I am trying to derive a triple angle formulae for tan. I know i need to use compound and double angle formulae but am finding it difficult to "clean" up my fraction to get the triple angle formulae can you show me a worked derivation?! thanks Answered by Penny Nom. 





sin(3a), cos(3a) and tan(3a) 
20070228 

From mailene: hi, i...indeed,to..need..your..help how..cn..i..prove..this,formula??? sin3a=3sina4sin^3a cos3a=4cos^33cosa tan3a=3tantan^3a /13tan^2a the..symbol...^is..the..expOnent Answered by Haley Ess and Penny Nom. 





Finding the missing side of a triangle 
20050120 

From Jason: I found a geometry problem that reads as follows:In triangle ABC, Answered by Penny Nom. 





Triple angle formula 
20000223 

From Sara: Can one derive a triple angle formula for sine and cosine? If so, how? Answered by Chris Fisher. 

