Question

5. If cos 20º = p and cos x = 2p^2 – 1, then the possible values of x between 0° and 360°
are
(a) 140°
(b) 40° and 140°
(C) 40° and 320°
(d) 50° and 130°​

Answer 1

Answer:

C

Step-by-step explanation:

cos2x = 2cos²x -1

using this 40° is clearly the first answer

also cos(360-x)=cosx

hence 320 is also an answer