Use x=4cos θ to

a)write as a trigonometric equation of θ, where 0<θ<π and x<0.

2√2=4sin θ

2√2=4(sin^{2}θ)

2√2=4(sin θ+cos θ)

2√2=sin ^{2}θ-cos^{2}θ

b)Find sin θ.

-√3/2

-√2/2

√2/2

√3/2

c)Find cos θ.