Find the exact value of sin 195° given sin 195°=sin (225°-30°)

Basically what I need to know is how sin 225° = -sin 45°....how do I know that sin 225° is equal to -sin 45°?

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- Apr 22nd 2008, 07:39 PMEricondaTrig exact values
Find the exact value of sin 195° given sin 195°=sin (225°-30°)

Basically what I need to know is how sin 225° = -sin 45°....how do I know that sin 225° is equal to -sin 45°? - Apr 22nd 2008, 07:43 PMMathstud28
- Apr 23rd 2008, 01:40 AMMoo