Here, As we are dealing with negative radian, we will go clockwise instead of counter-clock wise which we usually do in positive cases,
So, Terminal values are, 0, -π/2 , -π, -3π/2,
Now, You have: Sec (-4π/3)
Here, We can figure out, -π/3 is in between -π and -3π/2
so reference value = -π - (-4π/3) = Sec (π/3)
We know, Sec (π/3) = 2
As quadrant is 2th which is negative for sec, it would be -2
In short, Your Final Answer would be -2
Hope this helps!
