Question

sin²x+sinx cosx-2cosx-2cos²x=0

Answer 1

x1 = -2*atan((76 - (1 - sqrt(3)*i)*(8 - (1 - sqrt(3)*i)*(55 + 3*sqrt(426)*i)^(1/3))*(55 + 3*sqrt(426)*i)^(1/3))/(6*(1 - sqrt(3)*i)*(55 + 3*sqrt(426)*i)^(1/3)))
x2 = -2*atan((76 - (1 + sqrt(3)*i)*(8 - (1 + sqrt(3)*i)*(55 + 3*sqrt(426)*i)^(1/3))*(55 + 3*sqrt(426)*i)^(1/3))/(6*(1 + sqrt(3)*i)*(55 + 3*sqrt(426)*i)^(1/3)))
x3 = 2*atan(4/3 + 19/(3*(55 + 3*sqrt(426)*i)^(1/3)) + (55 + 3*sqrt(426)*i)^(1/3)/3)