Question 1067701: Can somebody help me by writing 4 cos 2θ sin 4θ as a sum or difference? Ty. Found 2 solutions by stanbon, ikleyn:Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! Can somebody help me by writing 4 cos 2θ sin 4θ as a sum or difference?
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a+b = 40
a-b = 20
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2a = 60
a = 30
Then b = 10
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4[cos(20)*sin(40)] = 4[cos(20-40)+cos(20+40)]
= 4[cos(20)+cos(60)]
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Cheers,
Stan H.
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You can put this solution on YOUR website! .
Can somebody help me by writing 4*cos(2*theta)*sin(4*theta) as a sum or difference? Ty.
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There is a general formula of Trigonometry
.
See any serious textbook in Trigonometry or the lessons
- FORMULAS FOR TRIGONOMETRIC FUNCTIONS
- Product of trigonometric functions
in this site.
This formula is FUNDAMENTAL, which means "everybody must know it".
According to this formula,
= = .
(