SOLUTION: I have to find the exact value for this expression: sin 260 degrees cos 20 degrees - cos 260 degrees sin 20 degrees help?

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Question 1035784: I have to find the exact value for this expression: sin 260 degrees cos 20 degrees - cos 260 degrees sin 20 degrees
help?

Answer by Boreal(15235)   (Show Source): You can put this solution on YOUR website!
This is of the form sin a*cos b-cos a*sin b
That is sin (a-b)=sin (260deg-20deg)=sin (240 deg)
That is the same as -sin (60 deg)=- sqrt(3)/2

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