SOLUTION: What is the general solution of 2cos²x + cosx - 1 = 0? Please and thanks!

                2cos²x + cosx - 1 = 0

That factors as:

        [2cos(x) - 1][cos(x) + 1] = 0

              2cos(x) - 1 = 0;   cos(x) + 1 = 0
                  2cos(x) = 1;       cos(x) = -1
                   cos(x) = ;    

If in degrees cos(x) =  has general solution

                  x = 60°+360°*k, and 300°+360°k

in radians
                  x = + and +

If in degrees cos(x) = -1 has general solution

                  x = 180°+360°*k

in radians
                  x = + 

Edwin