## MCQs for Chapter 3 Trigonometric Functions Class 11 with Answers

**Q1. If sin θ and cos θ are the roots of ax ^{2} – bx + c = 0, then the relation between a, b and c will be**

(a) a^{2} + b^{2} + 2ac = 0

(b) a^{2} – b^{2} + 2ac = 0

(c) a^{2} + c^{2} + 2ab = 0

(d) a^{2} – b^{2} – 2ac = 0

Correct option: (b) a^{2} – b^{2} + 2ac = 0

**Q2. The value of sin 50° – sin 70° + sin 10° is equal to**

(a) 1

(b) 0

(c) 1/2

(d) 2

Correct option: (b) 0

**Q3. The value of sin (45° + θ) – cos (45° – θ) is**

(a) 2 cosθ

(b) 2 sinθ

(c) 1

(d) 0

Correct option: (d) 0

**Q4. If α + β = π/4, then the value of (1 + tan α) (1 + tan β) is**

(a) 1

(b) 2

(c) – 2

(d) Not defined

Correct option: (b) 2

**Q5. If A lies in the second quadrant and 3 tan A + 4 = 0, then the value of (2 cot A – 5 cos A + sin A) is equal to**

(a) -53/10

(b) 23/10

(c) 37/10

(d) 7/10

Correct option: (b) 23/10

**Q6. Number of solutions of the equation tan x + sec x = 2 cos x lying in the interval [0, 2π] is**

(a) 0

(b) 1

(c) 2

(d) 3

Correct option: (c) 2

**Q7. If cos a + 2cos b + cos c = 2 then a, b, c are in**

(a) 2b = a + c

(b) b² = a × c

(c) a = b = c

(d) None of these

Ans: (a) 2b = a + c

**Q8. If the angles of a triangle be in the ratio 1 : 4 : 5, then the ratio of the greatest side to the smallest side is**

(a) 4 : (√5 – 1)

(b) 5 : 4

(c) (√5 – 1) : 4

(d) none of these

Ans: (a) 4 : (√5 – 1)

**Q9. The perimeter of a triangle ABC is 6 times the arithmetic mean of the sines of its angles. If the side b is 2, then the angle B is**

(a) 30°

(b) 90°

(c) 60°

(d) 120°

Ans: (b) 90°

**Q10. If the sides of a triangle are 13, 7, 8 the greatest angle of the triangle is**

(a) π/3

b) π/2

(c) 2π/3

(d) 3π/2

Ans: c) 2π/3