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Verifying Trigonomic Identities

  • Thread starter lucy1234
  • Start date
  • #1
2
0
Hey,

Can anyone help me solve this equation please?

Thanks

Homework Statement



cos(3θ)=cos3θ-3sin2θcosθ


Homework Equations



cos(u+v) = cosu cosv - sinu sinv
sin2u = 2sinu cosu

The Attempt at a Solution


Homework Statement





Homework Equations





The Attempt at a Solution

 

Answers and Replies

  • #2
2
0
I started with taking cosθ out of the equation, but got stuck from there
 
  • #3
33,098
4,797
Hey,

Can anyone help me solve this equation please?

Thanks

Homework Statement



cos(3θ)=cos3θ-3sin2θcosθ


Homework Equations



cos(u+v) = cosu cosv - sinu sinv
sin2u = 2sinu cosu
I would start in on the left side.
cos(3θ) = cos(2θ + θ) = ?
 
  • #4
559
8
cos3x = cos(2x+x) if that helps.
 
  • #5
33,098
4,797
I would start in on the left side.
cos(3θ) = cos(2θ + θ) = ?
cos3x = cos(2x+x) if that helps.
I think that's pretty much what I said.
 

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