document.write( "Question 21632: prove the following equation is an identity. show your work
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document.write( "sin5x+sin3x=4sin2xcos2xcosx\r
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document.write( "first i did the regular formula sinA+sinB=2sin(a+b/2)cos(a-b/2) so it came out like this : 2sin4xcosx and now i'm stuck and i dont know where to go from that can anyone help? thanks\r
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Algebra.Com's Answer #10522 by venugopalramana(3286)![]() ![]() You can put this solution on YOUR website! YOU ALMOST GOT THE ANSWER..JUST A LITTLE FINISHING TOUCH IS NEEDED..SEE BELOW \n" ); document.write( "---------------------------------------------------------------------------- \n" ); document.write( "sin5x+sin3x=4sin2xcos2xcosx \n" ); document.write( "first i did the regular formula sinA+sinB=2sin(a+b/2)cos(a-b/2)...VERY GOOD \n" ); document.write( " so it came out like this : 2sin4xcosx......VERY GOOD \n" ); document.write( "and now i'm stuck and i dont know where to go from that ........WHAT IS THE PROBLEM NOW SEE THE ANSWER AND DO ..WE HAVE COS X WHICH IS OK ..BUT WE HAVE SIN 4X AGAINST SIN 2X COS 2X.....HOPE YOU KNOW THE FORMULA SIN 2X=2 SIN X*COS X \n" ); document.write( "IT IS DERIVED FROM SIN(A+B)=SIN A*COS B+COS A*SIN B..BY PUTTING A=B.. \n" ); document.write( "SO WE GET SIN 4X=SIN 2*(2X)=2*SIN 2X*COS 2X....HENCE \n" ); document.write( "SIN 5X+SIN 3X= 2*(SIN 2X) *(COS 2X) *(2*COS X)=4 SIN 2X COS 2X COS X \n" ); document.write( " |