If 4 cos2 A - 3 = 0 and 0° ≤ A ≤ 90°; find: (i) angle A (ii) cos 3 A (iii) tan2 A + cos2 A

(i) 4 cos2 A - 3 = 0 ⇒ 4 cos2 A = 3 ⇒ cos2 A = ⇒ cos A = ⇒ cos A = ⇒ cos A = cos 30° ⇒ A = 30° Hence, the value of angle A = 30°. (ii) cos 3A = cos (3 x 30°) = cos 90° = 0 Hence, the value of cos 3A = 0. (iii) Hence, the value of tan2 A + cos2 A = .