Prove that: Sin 22 + sin 38 - sin 98 = 0
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sinc -sind= 2cos(c+d/2)sin(c-d/2)
sin 22-sin 98= 2cos(22+98/2)sin(22-98/2)
2cos60sin(-38)= -sin38
hence sin 38-sin 38=0
sin 22-sin 98= 2cos(22+98/2)sin(22-98/2)
2cos60sin(-38)= -sin38
hence sin 38-sin 38=0
Dima:
Thank you so much! I have different rules to go by but this one is different but better, the rule in my trig book goes like this : sin(A-B) = SinA Cos B - Cos A Sin B
the formula i wrote is in fact a modification of the one you wrote
just add sin (A-b) with sin (a+b) and place A+B=C and A-B=D
Got it! Thanks again
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sin22
sin 23
sin 24
sin 25
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