- #1
Melawrghk
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Homework Statement
#1. Solve the system:
3cos(a) + cos(b) +5sin(2a)=2
cos(a)=cos(b)+sin(2a)
7cos(a) + 13sin(2a)=-7cos(b)
The Attempt at a Solution
#1. I decided to substitute variables for sines and cosines. So I made cos(a) = x, cos(b)=y and sin(2a)=z, as a result of which, my equations now look like:
3x+y+5z=2
x-y-z=0
7z+7y+13z=0
after which I created the matrix, here is a picture of how I solved it. So I got -3/8 for "x" and entered it (it only asks for cos(a)), but it tells me I'm wrong. Am I being dumb and making some obvious error? Because I entered all equations with variable values into my calculator and they work out...
Thanks...
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