Math
posted by Sydney on .
Hi, I'm really having problems with this question, can someone please help me. Thankyou!
Algebraically solve for 0<phaeta<2pi, 2cos^2 phaeta7 cos phaeta +3=0

allow me to use x instead of 'phaeta' for ease of typing, so
cos^2 x  7cosx + 3 = 0
(2cosx  1)(cosx  3) = 0
cosx = 1/2 or cosx = 3, the latter not possible.
if cosx=1/2,then x = pi/3 or 5pi/3 (60º or 300º)