## Revision Notes for ICSE Class 10 Math Chapter 21 - Free PDF Download

## FAQs on ICSE Class 10 Mathematics Revision Notes Chapter 21 - Trigonometrical Identities

**1. Following concepts taught in class 10 ICSE Maths Chapter 21, show that**

= sin A cos A – sin 3 A cos A – cos 3 A sin A

= sin A cos A – sin A cos A (sin2 A + cos2 A)

= sin A cos A – sin A cos A (1) [[Since, sin2 A + cos2 A = 1]]

= 0

2. Following concepts taught in class 10 ICSE Maths Chapter 21, solve this: (sin A + cosec A)2 + (cos A + sec A)2 = 7 + tan2 A + cot2 A

L.H.S. = (sin A + cosecA)^{2} + (cosA+ secA)^{2}

= sin^{2} A + cosec^{2} A + 2 sin A cosec A + cos^{2} A + sec^{2} A + 2 cos A sec A

= sin^{2} A+cosec^{2} A+2 sin A x

1/sinA + cos^{2} A+sec^{2}A + 2cosA x 1/cosA

= sin^{2}A + cos^{2} A + cosec^{2} A + sec^{2}A+ 2 + 2 (∵ sin^{2} A + cos^{2}A= 1)

= 1 +cosec^{2}A + sec^{2}A + 4

= (1 + cot^{2} A) + (1 + tan^{2} A) + 5 [[∵ cosec ^{2}A = 1 + cot^{2} A and sec^{2} A = 1 + tan^{2}A]]

= 1 + cot^{2} A + 1 + tan^{2} A + 5

= 7 + tan^{2}A + cot^{2}A = R.H.S.

**3. How and where can I obtain some tricks and tips so that I can get high marks in ICSE Mathematics in class 10?**

There are some tips contained in this article that can help you score excellent marks in class 10 Maths for ICSE:

1. The requirement for every student to have access to a textbook that covers the entire syllabus for Class 10 Mathematics is vital. In addition to providing students with economic concepts, ICSE Book solutions can also assist them in understanding them more comprehensively.

2. So that you can recall the definitions easily during the examination, you should memorize and understand them quickly. It is imperative that you understand the meanings of each concept and have a good understanding of each definition. At the same time, make sure you understand the topic and concept, as well as the reasons behind them. It's important to establish that concepts have been derived from theories. The key to solving the problem quickly is to become familiar with each.

**4. How is self-study from revision notes important if you want to succeed in class 10 ICSE mathematics?**

The following ways for self-study from revision notes can be useful if you want to succeed in mathematics:

1.When you study on your own, it gives you the focus you need to excel in math. You will be able to focus on all the key aspects of the chapter that might otherwise get missed at the time when reading the chapter.

2. By self-study, you can understand each and every tough concept in Mathematics as you are practicing the questions by yourself, you are solving the doubts easily.

**5. What is the best way to prepare for Chapter 21 - Trigonometric Identities Class 10 Mathematics?**

For Chapter 21 - Trigonometric Identities Class 10 Mathematics, use these study points:

The first and most important thing you should do when you are preparing for Trigonometric Identities is to understand the details of the topic that has been explained.

Finding out the relevant information in the question tends to be the key to understanding a trigonometric equation

You will learn the topics much better if you take notes of the important elements of their presentation.

For a detailed understanding of this topic, you might consult Vedantu directly.