Question

PLEASE HELP!!! I've attached a file.

Answer 1

which one do you want?

Answer 2

all of them... haha.

Answer 3

but whichever you want to to is fine.

Answer 4

me confused!!

Answer 5

number 5 looks fun to me:
2sin²(x)-1=0
sin²(x)=0.5
sin(x)=0.5*sqrt(2) or sin(x)=-0.5*sqrt(2)
x=0.25pi + 2kpi or x=0.75pi + 2kpi or x=-0.25pi + 2kpi=1.75pi+2kpi or x=1.25pi+2kpi

so overall, this is the same as x=0.25pi + 0.5kpi