Register to reply

Trigonometric Proof

by likearollings
Tags: proof, trigonometric
Share this thread:
likearollings
#1
Mar15-11, 11:58 AM
P: 27
I am not quite sure how to prove this,

I can see it involves using a double angle formula (see http://mathworld.wolfram.com/Double-AngleFormulas.html).

I have tried working backwards but to no avail.

Any ideas?



Uploaded with ImageShack.us
Phys.Org News Partner Science news on Phys.org
Experts defend operational earthquake forecasting, counter critiques
EU urged to convert TV frequencies to mobile broadband
Sierra Nevada freshwater runoff could drop 26 percent by 2100
AlephZero
#2
Mar15-11, 01:07 PM
Engineering
Sci Advisor
HW Helper
Thanks
P: 7,177
Use
[tex]\sin a \cos b = (\sin (a+b) + \sin(a-b))/2[/itex]
likearollings
#3
Mar15-11, 01:12 PM
P: 27
Thanks! I will give that a go

likearollings
#4
Mar15-11, 01:29 PM
P: 27
Trigonometric Proof

Quote Quote by AlephZero View Post
Use
[tex]\sin a \cos b = (\sin (a+b) + \sin(a-b))/2[/itex]
Thanks, I managed to do it using

[tex]
\cos a \sin b = (\sin (a+b) - \sin(a-b))/2
[/tex]

PROBLEM SOLVED!


Register to reply

Related Discussions
Proof of trigonometric multiplication of complex numbers General Math 2
Trigonometric Identities Proof Precalculus Mathematics Homework 2
Trigonometric Proof Help Precalculus Mathematics Homework 12
Trigonometric Substitution Proof Calculus & Beyond Homework 3
Solving trigonometric equations Calculus & Beyond Homework 4