Question

Trigonometry
Trigonometric Equations
0 ≤ x ≤ 2 π, solve the equation 4 sec x +8=0

Answer 1

x = 2π/3, 4π/3

Explanation:

4secx = -8

secx = -2

cosx = -½

basic angle = π/3

x = π - π/3, π + π/3

x = 2π/3, 4π/3

Answer 2

Explanation:

4 sec x=-8

secx=-2

cos x=-1/2=-cos π/3=cos(π-π/3),cos (π+π/3)

=cos (2π/3),cos(4π/3)

x=2π/3,4π/3