Question

If cos x + sec x = -2, then for a positive integer n, cos^n x + sec^n x is
a) 2
b)-2
1-2 if n is odd and 2 if n is even
d) - 2 if n is even and 2 if n is odd​

Answer 1

If a b c are continued proportional fund 1/b^2 = 1/b^2-a^2 + 1/b^2 - c^2