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°?
Follow Math Help Forum on Facebook and Google+
Originally Posted by Ericonda 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°? you can multiply
Originally Posted by Ericonda how do I know that sin 225° is equal to -sin 45°? Hello, Because 225°=180+45 And if you look at a unit circle, sin(180+x)=-sin(x)
View Tag Cloud