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mmrproblem
Joined: 05 Nov 2004Posts: 17
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Posted: Tue Apr 12, 2005 5:26 am Post subject: trigonometry
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sinx+sin2x+sin3x+sin4x=sin78*sin84 then find x=?
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ariesfan
Joined: 04 Nov 2003Posts: 15
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Posted: Wed Apr 13, 2005 1:45 am Post subject:
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For the modified problem below, sinx+sin2x+sin3x+sin4x=2sin78*sin84 is eqivalent to 2sin(5x/2)[cos(3x/2)+cos(x/2)]=cos6+cos18 clearly x=12 will fit.But I guess there are infinitely many other solutions in the real line.
Can anyone hlep to find them all?~
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