Answer:
x = 120°
Step-by-step explanation:
We are given;
sec²x + 4secx = -4
Rearranging gives;
sec²x + 4secx + 4 = 0
Factorizing the left hand side gives;
(sec x + 2)(sec x + 2) = 0
This means that;
(sec x + 2) = 0
From trigonometry, we know that sec x = 1/cos x
Thus;
(1/cos x) + 2 = 0
1/cos x = -2
cos x = -1/2
cos x = -0.5
x = cos^(-1) -0.5
x = 120°
