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Trig. Identity

  • Thread starter morr485
  • Start date
  • #1
9
0
1. Verify this identity: a*sin Bx + b*cos Bx = sqrt(a^2 + b^2)sin(Bx + C)
where C= arctan b/a



2. a/sqrt(a^2+b^2)sin Bx + b/sqrt(a^2+b^2)cos Bx=cos C sin Bx + sin C cos Bx=



3.a*sin Bx + b cos Bx = sqrt(a^2 + b^2) sin(Bx + C)



Homework Statement





Homework Equations





The Attempt at a Solution

 
Last edited:

Answers and Replies

  • #2
danago
Gold Member
1,122
4
First thing that jumps to my mind is to make use of the trig expansion:

[tex]R sin(Bx+C)=R(sin(Bx) cos(C)+cos (Bx)sin(C))[/tex]
 
  • #3
9
0
danago thanks for the hint.
 

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