Question 863454
Determine all solutions of the given equation. Express in radians.
2(cosx)^2-sinx-1=0
***
{{{2cos^2(x)-sin(x)-1=0}}}
{{{2(1-sin^2(x))-sin(x)-1=0}}}
{{{2-2sin^2(x)-sin(x)-1=0}}}
{{{-2sin^2(x)-sin(x)+1=0}}}
-2sin^2(x)-sin(x)+1=0
2sin^2(x)+sin(x)-1=0
(2sin(x)-1)(sin(x)+1)=0
..
sin(x)=1/2
x=π/3+2πn, 5π/3+2πn, n=integer
or
sin(x)=-1
x=2π/3+2πn, n=integer