Question 1022070
cos^2 x + sin^2 x+ sin^2 x-2=0, splitting the 2 sin^2 x
the first two terms add to 1; cos^2 x+ sin^2x=1
1+sin^2 x-2=0
sin^2 x-1=0
(sin x+1)=0 (sin x-1)=0
sin x = 1 and -1