lets do one from each section for
3. cos(-630)
i would find out what quadrant it is in to eliminate positives and negatives. In this case the options are all positive but i will still include my tip.
a trick i learned is the acronym All Students Take Calc so in quadrant 1 (All) everything is positive. In quadrant 2 (Students) everything but sine is negitive. quadrant 3(take) everything but tangent is negitive, quadrant 4(Calc) everything but cosine is negitive.
so i would add 360 to -630 until i get a number equal to or less than 360 but positive.
-630+360= -270
-270+360= 90
we know that is is on the positive side of the y axsis. so we can refer to out circle with points on it, ill link one if you dont have one. so now we know thw answer is 0 because cosine is the x corrdinate.
