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View Full Version : Trigonometry qusetion

wazhma1991
Mar 15, 2009, 06:53 AM
sin(-2A)=-2sinAcos(-A)
vitaminh
Mar 21, 2009, 07:30 AM
yes: use some basic identities: sin(2A) = 2sin(A)cos(A) , sin(-A)=-sin(A), cos(-A)=cos(A)