Title TRIGONOMETRIC FUNCTIONS Q-2.pdf ✅

Class : XIth Subject : MATHS Date : DPP No. : 2 1. (1 + cos π 8 )(1 + cos 3π 8 )(1 + cos 5π 8 )(1 + cos 7π 8 ) is equal to a) 1 2 b)cos π 8 c) 1 8 d)1 + 2 2 2 2. If 2sin A 2 = 1 + sinA + 1 ― sinA, then A 2 lies between a) 2n π + π 4 and 2n π + 3π 4 , n ∈ Z b)2n π ― π 4 and 2n π + π 4 , n ∈ Z c) 2n π ― 3 π 4 and 2n π ― π 4 , n ∈ Z d) ―∞ and +∞ 3. In a ∆ABC, if acos2 C 2 + c cos2 A 2 = 3b 2 , then a,b,c are in a) A.P. b)G.P. c) H.P. d)None of these 4. The value of tan 5θ is a) 5 tan θ ― 10 tan3 θ + tan5 θ 1 ― 10 tan2 θ + 5 tan4 θ b) 5 tan θ + 10 tan3 θ ― tan5 θ 1 + 10 tan2 θ ― 5 tan4 θ c) 5 tan5 θ ― 10 tan3 θ + tan θ 1 ― 10 tan2 θ + 5 tan4 θ d)None of these 5. If the sides a,b and c of a ∆ABC are in A.P., then (tan A 2 + tan C 2 ):cot B 2 , is a) 3 :2 b)1 :2 c) 3 :4 d)None of these 6. If in a triangle ABC 2 cosA a + cosB b + 2 cos C c = a bc + b ca , then the value of the angle A is a) π 3 b) π 4 c) π 2 d) π 6 7. The value of tanα + 2 tan(2α) + 4 tan(4α) + ... + 2 n―1 tan(2 n―1α) + 2 n cot(2 n α) is a) cot (2 n α) b)2 n tan(2 n α) c) 0 d)cot α 8. The maximum value ofcos2 ( π 3 ― x) ― cos2 ( π 3 + x) is a) ― 3 2 b) 1 2 c) 3 2 d)3 2 9. If a = 2,b = 3,c = 5 in ∆ABC, then C = a) π 6 b) π 3 c) π 2 d)None of these 10. If in a ∆ABC, a cosA = b cosB , then Topic :- TRIGONOMETRIC FUNCTIONS