Question

how to find out the value of sec(-960) 'manually'.and how do we decide the sign of the answer at the end?

Answer 1

first divide by 360
-960/360 = 2 remainder - 240
-240 degrees is equivalent to 120 degrees
sec = 1/cos
cos 120 degrees = - cos 60 degrees = -1/2 (second quadrant cos is negative)
sec = 1 /-1/2 = -2

sec (-960) = -2

Answer 2

can you explain the general method,that i can apply to all functions of any kind of angle?