#### Chapters

Chapter 2: Polynomials

Chapter 3: Pair of Linear Equations in Two Variables

Chapter 4: Quadratic Equations

Chapter 5: Arithmetic Progressions

Chapter 6: Triangles

Chapter 7: Coordinate Geometry

Chapter 8: Introduction to Trigonometry

Chapter 9: Some Applications of Trigonometry

Chapter 10: Circles

Chapter 11: Constructions

Chapter 12: Areas Related to Circles

Chapter 13: Surface Areas and Volumes

Chapter 14: Statistics

Chapter 15: Probability

#### NCERT Mathematics Class 10

## Chapter 8: Introduction to Trigonometry

#### Chapter 8: Introduction to Trigonometry Exercise 8.30 solutions [Pages 189 - 190]

Evaluate `(sin 18^@)/(cos 72^@)`

Evaluate `(tan 26^@)/(cot 64^@)`

Evaluate cosec 31° − sec 59°

Show that cos 38° cos 52° − sin 38° sin 52° = 0

If tan 2A = cot (A – 18°), where 2A is an acute angle, find the value of A

If tan A = cot B, prove that A + B = 90

If sec 4A = cosec (A− 20°), where 4A is an acute angle, find the value of A.

Express sin 67° + cos 75° in terms of trigonometric ratios of angles between 0° and 45°

#### Chapter 8: Introduction to Trigonometry Exercise 8.40 solutions [Pages 193 - 194]

Express the trigonometric ratios sin A, sec A and tan A in terms of cot A.

Write all the other trigonometric ratios of ∠A in terms of sec A.

Evaluate

`(sin ^2 63^@ + sin^2 27^@)/(cos^2 17^@+cos^2 73^@)`

Evaluate sin25° cos65° + cos25° sin65°

Choose the correct option. Justify your choice.

9 sec^{2} A − 9 tan^{2} A =

1

9

8

0

Choose the correct option. Justify your choice.

(1 + tan θ + sec θ) (1 + cot θ − cosec θ)

0

1

2

-1

Choose the correct option. Justify your choice.

(secA + tanA) (1 − sinA) =

secA

sinA

cosecA

cosA

Choose the correct option. Justify your choice.

`(1+tan^2A)/(1+cot^2A)`

sec

^{2 }A−1

cot

^{2 }Atan

^{2 }A

Prove the following identities, where the angles involved are acute angles for which the expressions are defined

`(cosec θ – cot θ)^2 = (1-cos theta)/(1 + cos theta)`

Prove the following identities, where the angles involved are acute angles for which the expressions are defined

`cos A/(1 + sin A) + (1 + sin A)/cos A = 2 sec A`

Prove the following identities, where the angles involved are acute angles for which the expressions are defined

`(tantheta)/(1-cottheta) + (cottheta)/(1-tantheta) = 1+secthetacosectheta`

Prove the following identities, where the angles involved are acute angles for which the expressions are defined.

`(1+ secA)/sec A = (sin^2A)/(1-cosA)`

[Hint : Simplify LHS and RHS separately]

Prove the following identities, where the angles involved are acute angles for which the expressions are defined.

`(cos A-sinA+1)/(cosA+sinA-1)=cosecA+cotA`

Prove the following identities, where the angles involved are acute angles for which the expressions are defined.

`sqrt((1+sinA)/(1-sinA)) = secA + tanA`

`(sin theta-2sin^3theta)/(2cos^3theta -costheta) = tan theta`

## Chapter 8: Introduction to Trigonometry

#### NCERT Mathematics Class 10

#### Textbook solutions for Class 10

## NCERT solutions for Class 10 Mathematics chapter 8 - Introduction to Trigonometry

NCERT solutions for Class 10 Maths chapter 8 (Introduction to Trigonometry) include all questions with solution and detail explanation. This will clear students doubts about any question and improve application skills while preparing for board exams. The detailed, step-by-step solutions will help you understand the concepts better and clear your confusions, if any. Shaalaa.com has the CBSE Mathematics Textbook for Class 10 solutions in a manner that help students grasp basic concepts better and faster.

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Concepts covered in Class 10 Mathematics chapter 8 Introduction to Trigonometry are Trigonometric Ratios of Complementary Angles, Trigonometric Identities.

Using NCERT Class 10 solutions Introduction to Trigonometry exercise by students are an easy way to prepare for the exams, as they involve solutions arranged chapter-wise also page wise. The questions involved in NCERT Solutions are important questions that can be asked in the final exam. Maximum students of CBSE Class 10 prefer NCERT Textbook Solutions to score more in exam.

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