homework help > math > algebra thru pre-calculus q&a board > topic: simple...

Q BgQuestion:

      
Novice
Karma Points: 28
Respect (86%):
posted by  Dima09XX on 7/29/2009 4:36:05 PM  |  status: Closed  |  Earned Karma: 28

simple

Course Textbook Chapter Problem Needs by
N/A N/A N/A N/A N/A
Question Details:
Prove identity is true: sin6t=3sin2t-4sin32t
Bonus Point Alert! Earn +2 additional karma points for helping this gold member.

AAnswers:

Answer Question Ask for clarification
Oracle
Karma Points: 10,591
posted by wchau on 7/29/2009 4:45:30 PM  |  status: Live
Asker's Rating: Lifesaver   
Response Details:
We have






.
Thus .
Using the last proven identity with , we have .
Please consider rating my solution Lifesaver if you find that my solution is the best solution among all available solutions or it is the only solution available!
Apprentice
Karma Points: 194
posted by mukulg on 7/29/2009 4:49:20 PM  |  status: Live
Asker's Rating: Helpful   
Response Details:
LHS
=sin6t
 = sin3(2t)
 = sin (2(2t)+2t)
= sin(2(2t)cos2t)+cos(2(2t))sin(2t)
= sin2t*(2cos22t)+sin2t*(1-2sin22t)
=sin2t[2(1-sin22t)+(1-2sin22t)]
=sin2t[3-4sin22t]
=3sin2t-4sin32t
=RHS

proved...
Answer Question Ask for clarificarion
Ask New Question

Join Cramster's Community

Cramster.com brings together students, educators and subject enthusiasts in an online study community. With around-the-clock expert help and a community of over 100,000 knowledgeable members, you can find the help you need, whenever you need it. Join for free today » How Cramster is different from tutoring »

Need Help In

Useful Links