Functions
ICSE · Class 12 · Mathematics
Summary of Functions for ICSE Class 12 Mathematics. Key concepts, important points, and chapter overview.
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A function is a special type of relation in which every element of the domain has exactly one image in the co-domain. The chapter builds the idea of a function from basic mappings to real functions, then studies important types such as one-one, onto, and bijective functions. It also covers domain, c
Key Concepts
A relation from a set
A relation from a set A to a set B is a function if every element of A has exactly one image in B. A function is written as f: A → B.
The domain is the set from
The domain is the set from which inputs are taken, the co-domain is the target set, and the range is the set of all actual images. Range is always a s
Important examples include constant
Important examples include constant, identity, polynomial, rational, linear, square, square root, reciprocal, modulus, floor, ceiling, signum, exponen
A function is one
A function is one-one if different elements of the domain have different images. Equivalently, if f(a) = f(b), then a = b. The horizontal line test ch
A function is onto if every
A function is onto if every element of the co-domain has at least one pre-image in the domain. In this case, range equals co-domain.
Learning Objectives
- Understand the meaning of a function as a special relation
- Identify domain, co-domain, and range of a function
- Classify functions as one-one, onto, or bijective
- Use graphical tests to check whether a curve represents a function and whether it is one-one
- Study standard real functions and their domains and ranges
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