Better Students Ask More Questions.
if `sin^(2) theta + sin^(2) 2theta + sin^(2) 3 theta= 1` what does `cos^(2) 3 theta...
1 Answer | add yours
High School Teacher
Best answer as selected by question asker.
For any value of `theta,`
`sin^2 theta+cos^2 theta=1` (1)
`sin^2 2theta+cos^2 2theta=1` (2)
`sin^2 3theta+cos^2 3theta=1` (3)
Thus, if we add equations (1), (2), and (3), we get`sin^2 theta+sin^2 2theta+sin^2 3theta`
`+cos^2 theta+cos^2 2theta+cos^2 3theta=3.`
It is given that `sin^2 theta+sin^2 2theta+sin^2 3theta=1,` so we must have `cos^2 theta+cos^2 2theta+cos^2 3theta=2.`
Posted by degeneratecircle on July 14, 2013 at 11:43 PM (Answer #1)
Join to answer this question
Join a community of thousands of dedicated teachers and students.