8 cos^2 x/2+ 6 sin x/2-3=0

Question

8 cos^2 x/2+ 6 sin x/2-3=0

Answer 1

8-8sinx/2+6sinx/2-3=0
sinx/2=a
8a²-6a-5=0
D=36+160=196
a1=(6-14)/16=-0,75⇒sinx=-0,75⇒x=(-1)^(n+1)*arsin0,75+πn,n∈z
a2=(6+14)/16=1,25⇒sinx=1,25>1 нет решения