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Math Forum » Discussions » Math Topics » geometry.college.independent

Topic: Trigonometric Equation
Replies: 5   Last Post: Dec 24, 2006 1:45 AM

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Vijaya Prasad Nalluri

Posts: 8
From: India
Registered: 4/10/06
Re: Trigonometric Equation
Posted: Nov 20, 2006 11:30 AM
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By direct verification
2 sin 24 sin 84 = cos 60 - cos 108 = 1/2 + sin 18
2 sin 30 sin 54 = sin 54 = cos 36
Note cos 36 - sin 18 = 1/2
etc
Prasad
> How can I prove that x=30 "exactly" is the solution
> of the following equation?
>
> sin(54-x) / sinx = sin54 / sin84
>
> All I've been able to find is x=arctan[(sin84sin54) /
> (sin54 + sin84cos54)] approximately equal to 30
>
> Thanks and regards.




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