Question

HELP!!
2sin^2 x - cos^2 x - 2 = 0

please show all work!

Answer 1

sin^2+cos^2=1 remember

Answer 2

cos^2=1-sin^2

Answer 3

now replace cos^2
2sin^2-(1-sin^2)-2=0
2sin^2-1+sin^2-2=0
3sin^2-3=0
3(sin^2-1)=0
sin^2-1=0
sin^2=1
sin=+-1
sin=n*pi/2

Answer 4

@ttop0816

Answer 5

thank you!