Question 679509
find all solutions if 
0_< theta < 360 
sin^2(2)x - 4sin2x - 1 = 0
solve for sin(2x) using following quadratic formula:
{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
a=1, b=-4, c=-1
ans:
sin(2x)=4.236 (reject, -1 &#8804; sin(2x) &#8804; 1)
or
sin(2x)&#8776;-0.236
2x&#8776;193.65º and 346.35º (in quadrants III and IV where sin<0
x=96.82º and 173.18º