Please help, I'm so confused Review the proof.

A 2-column table with 8 rows. Column 1 is labeled step with entries 1, 2, 3, 4, 5, 6, 7, 8. Column 2 is labeled Statement with entries cosine squared (StartFraction x Over 2 EndFraction) = StartFraction sine (x) + tangent (x) Over 2 tangent (x) EndFraction, cosine squared (StartFraction x Over 2 EndFraction) = StartStartFraction sine (X) + StartFraction sine (x) Over cosine (x) EndFraction OverOver 2 (StartFraction sine (x) Over cosine (x) EndFraction) EndEndFraction, cosine squared (StartFraction x Over 2 EndFraction) = StartStartFraction StartFraction question mark Over cosine (x) EndFraction OverOver StartFraction 2 sine (x) Over cosine (x) EndFraction EndEndFraction, cosine squared (StartFraction x Over 2 EndFraction) = StartStartFraction StartFraction (sine (x)) (cosine (x) + 1) Over cosine (x) EndFraction OverOver StartFraction 2 sine (x) Over cosine (x) EndFraction EndEndFraction, cosine squared (StartFraction x Over 2 EndFraction) = (StartFraction (sine (x) ) (cosine (x) + 1 Over cosine (x) EndFraction) (StartFraction cosine (x) Over 2 sine (x) EndFraction), cosine squared (StartFraction x Over 2 EndFraction) = StartFraction cosine (x) + 1 Over 2 EndFraction, cosine (StartFraction x Over 2 EndFraction) = plus-or-minus StartRoot StartFraction cosine (x) + 1 Over 2 EndFraction EndRoot, cosine (StartFraction x Over 2 EndFraction) = plus-or-minus StartRoot StartFraction 1 + cosine (x) Over 2 EndFraction EndRoot.

Which expression will complete step 3 in the proof?

sin2(x)
2sin(x)
2sin(x)cos(x)
sin(x)cos(x) + sin(x)