The function 𝑓 is given by 𝑓𝜃=cos2𝜃+cos𝜃−sin2𝜃
Rewrite 𝑓 using only cos𝜃 
Of the following, which are zeros of 𝑓?
(D) 3𝜋2 
(E) arccos23 
(F) 𝜋−arccos23
(G) 𝜋+arccos23 
(H) 2𝜋−arccos23 
(I) 2𝜋+arccos23
(A) 0 
(B) 𝜋2 
(C) 𝜋