Trigonometry is the branch of mathematics for solving the geometric problems related to triangles. Students of class 11 cannot skip the chapter of Trigonometric Functions, because this is useful in many areas like finding the heights of tides in the ocean, designing electronic circuits and many more. In the previous classes, students have already studied the trigonometric identities and applications of trigonometric ratios. Trigonometric Functions formula has a wide application for the students. Students must study these concepts systematically so that it should become easy and interesting for them.

In this chapter, the student will learn about the trigonometric functions and their representations. Also, they will learn finite and infinite trigonometric functions, equal trigonometric functions. Sub trigonometric functions etc. Properties of the complement trigonometric functions are also an important part of this chapter.

Trigonometry word is the combination of trigonon (means triangle) and metron (means measurement). So, we can say that trigonometry means the measurement of a triangle. A triangle is having six measurements of 3-sides and 3-angles. Therefore, to determine the relationship between sides and angles we need to study trigonometry. Students are very much familiar with the basics of trigonometry, but in this chapter, the student will learn interesting facts about the trigonometry. Many problems of Calculus, Matrices, and Determinant, and Functions are solvable easily using the tricks of trigonometric functions.

Some important subtopics of this chapter are Angles and their measures, the relation between radian and real numbers, Trigonometric Functions, Sign, domain, and range of trigonometric functions, Trigonometric Functions for the sum and difference of two Angles and Trigonometric Equations.

As every function have both domain and range, so here the student will study the range and domain of every trigonometry function and their behaviour. This chapter will explain all the identities formed with the help of these functions. This will help to understand the trigonometry, and finally, multi-concept problems for solving using these concepts.

The subtopic of trigonometric equations will provide methods to find general solutions to all the trigonometric functions. The contents of this chapter are interactive and with numerous examples with variety. The student will find the definition of trigonometric functions with relevant identities. Trigonometric functions are also having the argument, which is the angle in this case. Trigonometric functions are describing the relation between the sides and angles of a right triangle. Applications of trigonometric functions are extremely diverse in the nature of applications. For example, we may use some of the trigonometric functions (i.e. Fourier series) with periodic processes. These functions are often visible in the solution of differential equations and functional equations.

The trigonometric functions will include the functions for sine, cosine, tangent, cotangent, secant, and cosecant. For each of these functions, there is also an inverse trigonometric function. After studying the trigonometric functions students will be able to understand the trigonometry identities as well as to resolve the problem based on the periodic functions.

With the help of these concepts reader of this chapter will understand not only the basic trigonometric identities, trigonometric ratios of allied angles, but also the difference of two angles, conditional identities with witness graphs of trigonometric functions.