In this chapter, we will study about one of the most important concepts in mathematics known as a function. Functions form one of the most important building blocks of mathematics. The word “Function” is derived from a Latin word meaning operation and the words mapping and map synonymous to it. Functions play very important role in differential and integral calculus which will be dealt in XII class. In this chapter, we shall introduce the concept of a function as a correspondence between two sets. We shall also study function as a relation from one set to the other set.
Easy examples are given in which we will discuss some standard real functions which frequently occur in the study of calculus. Some of the important functions that will be discussed in the RD Sharma exercises are identity functions, modulus function, Greatest Integer function, Ceiling Function, exponential function, Logarithmic function, Reciprocal, square root and cube root function and different operations on real function. Practise and understand these concepts in a structured manner using the solved examples in the the given RD Sharma solutions for the chapter “Functions”.
Chapter 3 Functions 

Functions Exercise 3.2  
Functions Exercise 3.3 