 # CBSE 10th Maths Important MCQs from Chapter 8 Introduction to Trigonometry with Detailed Solutions

Get MCQs on Class 10 Maths Chapter 8 - Introduction to Trigonometry with answers in PDF. CBSE 10th Maths Important MCQs from Chapter 8 Introduction to Trigonometry with Detailed Solutions

MCQ questions for class 10 Maths Chapter 8- Introduction to Trigonometry are provided here. All these MCQs are provided with answers and are important for CBSE Class 10 Maths Exam which will be conducted on 12th March, 2020. All the questions are also available in PDF. Practice with these questions to revise the important concepts and score good marks in the CBSE Class 10 Maths Exam 2020.

Check below solved MCQs from Class 10 Maths Chapter 8Introduction to Trigonometry:

1. (sin30° + cos30°) – (sin 60° + cos60°)

(A) – 1

(B) 0

(C) 1

(D) 2

Explanation: According to question 2. Value of tan30°/cot60° is:

(A) 1/√2

(B) 1/√3

(C) √3

(D) 1

Explanation: 3. sec2θ – 1 = ?

(A) tan2θ

(B) tan2θ + 1

(C) cot2θ – 1

(D) cos2θ

Explanation: From trigonometric identity

1+ tan2θ = sec2θ

⇒sec2θ – 1 = tan2θ

4. The value of sin θ and cos (90° – θ)

(A) Are same

(B) Are different

(C) No relation

(D) Information insufficient

Explanation: Since from trigonometric identities,

cos(90° – θ) = sin θ

So, both represents the same value.

5. If cos A = 4/5, then tan A = ?

(A) 3/5

(B) 3/4

(C) 4/3

(D) 4/5

Explanation: From trigonometric identity 6. The value of the expression [cosec (75° + θ) – sec (15° - θ) – tan (55° + θ) + cot (35° - θ)] is

(A) 1

(B) −1

(C) 0

(D) 1/2

Explanation: Since

cosec (75° + θ) – sec (15° - θ) – tan (55° + θ) + cot (35° - θ)

= cosec (75° + θ) – cosec [90° - (15° - θ)] – tan (55° + θ) + tan [90° - (35° - θ)]

= cosec (75° + θ) – cosec (75° + θ) – tan (55° + θ) + tan (55° + θ)

= 0

7. Given that: SinA = a/b, then cosA = ? (C) b/a

(D) a/b

Explanation: We have 8. The value of (tan1° tan2° tan3° ... tan89°) is

(A) 0

(B) 1

(C) 2

(D)1/2

Explanation: This can be written as,

(tan1° tan2° tan3° ... tan89°)

(tan1° tan2° tan3° ....... tan44° tan45° tan46° ..... tan87°tan88°tan89°)

= [tan1° tan2° tan3° ....... tan44° tan45° tan (90 – 44)° ..... tan(90° - 3) tan (90° - 2) tan (90° - 1)]

= (tan1° tan2° tan3° ....... tan44° tan45° cot 44° ..... cot3° cot2° cot 1°)

= 1

Since tan and cot are reciprocals of each other, so they cancel each other.

9. If sin A + sin2 A = 1, then cos2 A + cos4 A = ?

(A) 1

(B) 0

(C) 2

(D) 4

Explanation: We have

sin A + sin 2 A = 1

⇒ sin A = 1 – sin2 A

⇒ sin A = cos2 A               ......(i)

Squaring both sides

⇒sin2A = cos4A               ......(ii)

From equations (i) and (ii), we have

cos2A + cos4A = sin A + sin2A = 1

10. If sin A = 1/2 and cos B = 1/2, then A + B = ?

(A) 00

(B) 300

(C) 600

(D) 900

Explanation: Since  (A) 3

(B) 2

(C) 1

(D) 0

Explanation: Using trigonometric properties, we have: 12. If cos9α = sin α and 9α < 90°, then the value of tan 5α is

(A) √3

(B) 1/√3

(C) 0

(D) 1

Explanation: Since

cos9α = sinα

⇒ sin (90° - 9α) = sinα

⇒ (90° - 9α) = α

⇒ α = 9°

Therefore,

tan 5α = tan 5 (9°)

= tan45°

= 1

13. If a pole 6m high casts a shadow 2√3 m long on the ground, then the sun’s elevation is

(A) 60°

(B) 45°

(C) 30°

(D)90°

Explanation: Given condition can be represented as follows:  14. If cos (A + B) = 0, then sin (A – B) is reduced to:

(A) cos A

(B) cos 2B

(C) sin A

(D) sin 2B

Explanation: Since

cos (A + B) = 0

⇒ cos (A + B) = cos90°

⇒ (A + B) = 90°

⇒ A = 90° - B

This implies

sin (A – B) = sin (90° - B - B)

⇒ sin (A – B) = sin (90° - 2B)

sin (A – B) = cos 2B (A) 2/3

(B) 1/3

(C) 1/2

(D) 3/4

Explanation: This can be solved as,  Also check below MCQs from other chapters of CBSE Class 10 Maths:

Important MCQs from Class 10 Maths Chapter 1

Important MCQs from Class 10 Maths Chapter 2

Important MCQs from Class 10 Maths Chapter 3

Important MCQs from Class 10 Maths Chapter 4

Important MCQs from Class 10 Maths Chapter 5

Important MCQs from Class 10 Maths Chapter 6

Important MCQs from Class 10 Maths Chapter 7

MCQs on remaining chapters will be provided here soon.

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CBSE Class 10 Maths Exam Pattern 2020 with Blueprint & Marking Scheme

CBSE Class 10 Maths Important Questions and Answers for Board Exam 2020

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