Question 285400: PLEASE HELP!!
1. If sin(theta)=1/2, then sin(-theta)=______, sin(pi - theta)=______, and sin(theta + pi)=________?
2. If cos(theta)=square root 3/2, then cos(-theta)=______, cos(pi - theta)=_____, and cos (theta + pi)=______ ?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! 1. If sin(theta)=1/2, then sin(-theta)= -1/2,
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sin(pi - theta)= sin(pi)cos(theta)-cos(pi)sin(theta) = 0-(-1)(1/2) = 1/2
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sin(theta + pi)= sin(theta)cos(pi)+cos(theta)sin(pi) = -sin(theta)+0 = -1/2
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2. If cos(theta)=(sqrt3)/2, then cos(-theta)=(sqrt3)/2,
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cos(pi - theta)= cos(pi)cos(theta)+sin(pi)sin(theta)= -cos(theta)= -(sqrt3)/2
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cos(theta+pi)=cos(theta)cos(pi)-sin(theta)sin(pi)=-cos(theta)= -(sqrt3)/2
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Cheers,
Stan H.
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