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#1 2009-08-16 17:29:13

yamini
Novice

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trig

please help me solving this question
sinx+siny=3/4  sinx -siny=2/5 then tan(x-y/2)/tan(x+y/2)

 

#2 2009-08-16 18:24:45

Identity
Power Member

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Re: trig



Seeing products of trig terms, the product to sum formula might be useful:







Now, to the other equations,





Adding,







Also, subtracting,





Now if x is in the first quadrant then we get


If x is in the second quadrant then we get

 

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