+129830 -7pi/4.....convert to + degrees thusly
-7/pi / 4 + 2pi = -7pi/4 + 8pi/4 = pi/4
So
tan (-7pi/4) = tan (pi/4) = 1
sec (pi/6) = 1 / cos (pi/6) = 1 / (sqrt (3) / 2 ) = 2 / sqrt (3)
cos (23pi/6)
23pi/6 = 3pi + 5/6 pi .....3pi puts us back at 180°.....(5/6) pi adds 150° to this = 330°
This is a 30° reference angle in the 4th quadrant
cos (30°) = sqrt (3) / 2
