SOLUTION: Verify,
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cosxcosy = 1/2 [cos(x+y) + cos(x-y)]
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My professor did not properly explain this. I don't understand how to solve the equation.
'
Thank You
Algebra ->
Trigonometry-basics
-> SOLUTION: Verify,
'
cosxcosy = 1/2 [cos(x+y) + cos(x-y)]
'
My professor did not properly explain this. I don't understand how to solve the equation.
'
Thank You
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Question 513387: Verify,
'
cosxcosy = 1/2 [cos(x+y) + cos(x-y)]
'
My professor did not properly explain this. I don't understand how to solve the equation.
'
Thank You Answer by lwsshak3(11628) (Show Source):
You can put this solution on YOUR website! verify:
cosxcosy = 1/2 [cos(x+y) + cos(x-y)]
starting from right side:
using addition formulas
1/2[(cosxcosy-sinxsiny)+((cosxcosy+sinxsiny)]
=1/2(2cosxcosy)=cosxcosy
verified:
right side = left side
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