Mark M. answered 03/15/21
Tutor
4.9
(954)
Retired math prof. Very extensive Precalculus tutoring experience.
csc(-145°) = csc(-145° + 360°) = csc215° = csc(35° + 180°) = 1 / [sin(35° + 180°) = -1/sin35°
So, 1 + 2csc(-145°)sin35° = 1 - 2 = -1