JEE Exam » JEE Study Material » Mathematics » Graphs of Functions

Graphs of Functions

In this article we will cover how graphs represent functions, how to graph a function, types of function graphs. The set of all points in the plane of the form (x, f(x)) is the graph of a function f. The graph of f can also be defined as the graph of the equation y = f(x). The graph of a function is thus a subset of the graph of an equation.

The process of drawing the graph (curve) of the corresponding function is known as graphing functions. Graphing basic functions such as linear, quadratic, cubic, and so on is fairly simple; however, graphing complex functions such as rational, logarithmic, and so on requires some skill and knowledge of mathematical concepts.

A function graph is the collection of all the points of a function plotted on a graph. The vertical line test can be used to determine the graph of a function. Simply draw vertical lines (lines parallel to the y axis) for each x value. Because a function has only one output for each input, if the vertical line intersects the x value more than once, the graph is not a function. If the vertical line crosses each x value only once.

How graphs represent functions

Graphing functions is the process of drawing a curve that represents a function on a coordinate plane. If a function is represented by a curve (graph), then every point on the curve satisfies the function equation. For example, the graph below depicts the linear function f(x) = -x+ 2.

Take any point along this line, for example (-1, 3). Let us replace (-1, 3) = (x, y) that is, x = -1 and (y = 3) in the function f(x) = -x + 2 (note that it can also be written as y = -x + 2). Then

3 = -(-1) + 2, 

3 = 1 + 2, 

3 = 1 + 2

3 = 3, so (-1, 3) fulfils the function. Similarly, you can experiment with different points to see if they satisfy the function. Every point on the line, which is commonly referred to as a “curve,” fulfils the function. Graphing functions is the process of drawing such curves to represent functions.

Graphing Fundamental Functions

It is simple to graph basic functions such as linear functions and quadratic functions. The fundamental concept of graphing functions is

If possible, identify the shape. If it is a linear function of the form f(x) = ax + b, its graph is a line; if it is a quadratic function of the form .  Its graph is a parabola.

Locating some points on it by substituting some random x values and locating the corresponding y values by substituting each value into the function

How to graph a function

For graphing functions, we must construct a table of values and plot its asymptotes, x and y-intercepts, holes, and a few points on it. Then simply join the point while avoiding the asymptotes and noting the domain and range of the function.

The following are the steps for graphing a  function:

  • Ascertain that the function has the form y=mx+b.

  • b is now plotted on the y-axis.

  • m is reduced to a fraction.

  • The slope is now used to extend the line from b.

  • The line can be extended further by using mm as a guiding factor.

So we only need two points on a linear function to graph it. To graph it, simply create a table of values with two columns x and y, select some random numbers for x, and calculate the corresponding y values by substituting each of them in the function. Then simply plot the points on a graph, connect them with a line, and extend the line on both sides indefinitely.

Types of function graphs

The graph of functions aids in the visualisation of the function given in algebraic form. By looking at an equation, you can tell whether the graph will be odd or even, increasing or decreasing, or whether the equation represents a graph at all.

  • Depending on the type of function graphed, different types of graphs exist.  linear, 

  • power

  • quadratic

  • polynomial

  • rational

  • exponential

  • logarithmic 

  • Sinusoidal

Conclusion

In this article we conclude that, A function’s graph is the set of all points in the plane of the form (x, f(x)). The graph of f could also be defined as the graph of the equation y = f. (x). As a result, the graph of a function is a subset of the graph of an equation. A function’s graph is frequently a useful way of visualising the relationship of the function models, and manipulating a mathematical expression for a function can shed light on the function’s properties. Many important phenomena can be modelled using functions presented as expressions.

faq

Frequently asked questions

Get answers to the most common queries related to the JEE Examination Preparation.

Function graphs are what kind of graphs?

Ans. Examine the graph to see if any vertical lines that are drawn intersect the curve more than once. If there is s...Read full

How Do You Draw an Equation Graph?

Ans. To draw a graph of a function’s equation, do the following:...Read full

How Do You Determine Whether a Graph Is a Function?

Ans. The vertical line test is always passed by a function. To perform this test, simply draw a vertical line (or si...Read full

What Is the Best Way to Graph a Piecewise Function?

Ans. In different intervals, a piecewise function is defined in various ways (using different equations). We simply ...Read full

Why are function graphs important?

Ans. A function’s graph is frequently a useful way of visualising the relationship of the function models, and...Read full