Question #79779

1 Answer
Bdub
Mar 8, 2016

sin(3theta)=sin(2theta+theta)=sin2thetacos theta+cos2theta sintheta
cos(3theta)=cos(2theta+theta)=cos(2theta)costheta-sin(2thetasintheta)
tan(3theta)=tan(2theta+theta)=(tan(2theta)+tantheta)/(1-tan(2theta)(tantheta))

Explanation:

sin(3theta)=sin(2theta+theta)=sin2thetacos theta+cos2theta sintheta
cos(3theta)=cos(2theta+theta)=cos(2theta)costheta-sin(2thetasintheta)
tan(3theta)=tan(2theta+theta)=(tan(2theta)+tantheta)/(1-tan(2theta)(tantheta))
Note you can simplify the double angles by using the appropriate double angle formula to dissolve it

Related questions
See all questions in Products, Sums, Linear Combinations, and Applications
Impact of this question
1555 views around the world
You can reuse this answer
Creative Commons License