hey thx. i did make a blunder
.thanks for pointing it out.sending u a salute.
i m trying to crack the problem in the right way. for the time being here is a soln of a problem by amar gupta that i got somewhere in this site.it may help
cos2theta=cos(theta+phi)
sin2theta= 2sin(theta+phi)
i am taking
=A and
= B. then 2sinA cosA =2sin(A+B) or sinA cosA =sin(A+B)......[1] and cos2A=cos(A+B)....[2] square and add: (sinA cosA)2 + (cos2A)2 = 1 or (sinA cosA)2 = 1- (cos2A)2
or (sinA cosA)2 = (sin2A)2
or (sinA cosA)2 = (2sinAcosA)2
or (sinA cosA)2 = 4(sinAcosA)2
or 3(sinAcosA)2 = 0 sinAcosA=0 hence either sinA =0 or cosA=0 when sinA=0 from eq.[1]: 0=sin(A+B) or cosAsinB=0 or sinB=0 or B=n (pie) where n is an +ve integer
when cosA =0 from eq.[1]: 0=sin(A+B) or sinAcosB=0 or cosB=0
B=[2k(pie)+(pie)/2] and B=[2k(pie) - (pie)/2] where k is an +ve integer
I dont know what exactly your question demands ,as you have not mentioned any thing that why you want to make eq. in
only. but i think this will also work.