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Last updated on September 14, 2025
A zero function is a function whose domain includes all the real numbers, but its range contains only one value. In this article, we will learn about zero function, its graph, and its characteristics.
A zero function is a constant function that, irrespective of the inputs, always results in zero as the output value. The zero function is not a one-to-one function because it assigns the value 0 to every input in its domain, meaning different inputs have the same output.
What is a Zero Function Graph?
The graph of a zero function, f(x) = 0, resembles the graphs of other constant functions that run parallel to the x-axis. Any function that has the formula y = k, where k is a constant real number, is considered a constant function. Another way to write it is f(x)=k. The graph of the zero function is a horizontal line along the x-axis, because the output (y-value) is always zero for every input.
The zero functions have several key properties, such as slope, domain, range, differentiability, limit, and continuity. Now, let’s examine the different properties of a zero function. The zero function shares characteristics with constant functions, since it is a type of constant function.
If f(-x)=f(x) for every value of x in the domain of f, then the function is said to be even; if f(-x)=-f(x) for every value of x in the domain of f, then the function is said to be odd. For all values of x in the domain of f, the zero function is the only function that satisfies both of these requirements simultaneously. The zero function is both odd and even. Since the output is always the same, f(-x)=f(x)=-f(x)=0 if f(x)=0 It is the zero function.
How to Find Zeros of Function
When real, complex, or imaginary values are entered into a function, the function is equal to zero. Depending on the type of function, there are different ways to find its zeros. When describing a function or creating its graph, zeros are important.
Finding a function’s zeros can be done in a number of ways, including:
A function’s graph can be used to determine its zeros. We are aware that the value of f(x) is zero for any zero of the function’s root. Therefore, the zeros of the function are represented by the x coordinate of each point where the graph of the function crosses the x-axis.
For example, the graph of the function f(x)=x2-25/16 intersects the x-axis. The zeros of the given function are x = 5/4 and x = -5/4, where the function equals zero.
Factorization Method
When a function can be broken down into smaller parts, the factorization method is a helpful technique. To use the factorization method and to find the function’s zeros, just break the function down into simple factors, set each factor to zero, and solve them. Equating both factors to zero is based on the step that one or both factors must be zero when the product of the expressions is zero. For example, the factorization method can be used to find the zeros of the function f(x)=x2-6x+5 as follows:
f(x)=x2-6x+5
f(x)= (x-5)(x-1)
put, x-5=0 and x-1=0
So, x=5 or x=1
Quadratic Formula Method
The quadratic formula is one of the best algebraic techniques for determining a function’s roots. The roots of a quadratic function can be found with this method. Simply enter the values of a, b, and c in the quadratic formula, where a, b, and c stand for the coefficients of x2, x, and the constant term, respectively, to determine the roots of a quadratic function using this method.
root=(-b+b2-4ac)/2a
Or
root =(-b-b2-4ac)/2a
Using this technique, one can find the real roots and the imaginary roots:
Real roots = b2-4ac>=0, real roots
Imaginary roots = b2-4ac<0
Newton-Raphson Method
One of the most popular methods for finding the roots of a real-valued function is the Newton-Raphson method. It bears the names of Joseph Raphson and Sir Isaac Newton. The Newton-Raphson method approximates the subsequent iteration (x1), which is near the root, after assuming the first iteration (x0). The Newton-Raphson method works as follows:
Given that x0 is the approximate root of the equation, let x1=x0+h be the root of the function.
Then, f(x1)=0 or f(x0+h)=0,
Applying Taylor’s theorem, expand the equation above.
f(x0)+hf1(x0)+...=0
Thus,
h=-f(x0)/f'(x0) or we could say
x1=x0-f(x0)/f'(x0)
Similarly, we can determine additional approximations for x2, x3, x4, etc.
Or
Xn+1=Xn-f(xn)/f' (xn)
This is called the Newton-Raphson formula.
Bisection Method
The root of a polynomial function within a specified interval can be found using the bisection method. Until the right answer is found, this method works by dividing the interval into smaller sub-intervals. For the functions that are continuous within a specified interval, this method is correct. Because of its strong similarity to binary search, it is also referred to as the interval having method or binary search method. The bisection method operates as follows:
Let x and y be such that x<y and f(x) x f(y)<0.
Find the midpoint of x and y in each interval (let’s say it’s m). If m is the right root, then f(m) = 0. Thus, we obtain the necessary root m.
If not, the interval will be split into two sections: x to m and m to y. We will now select the interval based on the value of f(m) as follows:
Select the interval from m to y if f(m) < 0. Because x < m < y.
Select the interval from x to m if f(m) > 0. Because x < m < y.
Continue repeating steps one through three until the right answer is found.
The zero function is used to represent the profit in a business and more. Let us see how the zero function helps in real life.
Students often make mistakes, like confusing the zero functions with functions and more. Let us look at the mistakes and how to quickly correct them.
f(x)=x2-6x+5 find the zeros of the function
f(x)=(x-5)(x-1)
Make all the factors equal to 0:
x-5=0 ⇒ x=5
x-1=0 ⇒ x=1
The values of x for which f(x) = 0 are the zeros of a function, to make it simple. The equation can be solved more easily by the factoring method. When x = 5 and x = 1, the function equals zero. Additionally, 5 and 1 are the zeros of the functions.
Find f(x)=3x-9
3x-9=0
Find x:
3x=9 ⇒ x=3
Now, we write the expression to 0 and solve for x to find the zero of a linear function. In this case, the function becomes zero when x = 3.
Find f(x)=x2-9
f(x)=(x-3)(x+3)
Make all the factors that are equal to 0:
x-3=0 ⇒ x=3
x +3=0 ⇒ x=-3
Here, the difference of squares formula a2-b2=(a-b)(a+b) is useful. The two zeros, x = 3 and x = -3, are obtained by solving both factors.
Find f(x)=x(x+4)
x(x+4)=0
Make all the factors zero:
x=0 or x+4=0 ⇒ x=-4
If at least one of the factors is said to be zero, then the product is also zero. Therefore, the function becomes zero at x=0 or x=-4.
Zero of the function f(x)=2x2-8x. Find
f(x)=2x(x-4)
Make all of the factors equal to 0:
2x=0 ⇒ x=0
x-4=0 ⇒ x=4
Here, factor out the greatest common factor (2x) first. To find the values of x at which the function becomes zero, now set each factor to zero. Thus, x=0 and x=4 are the function’s zeros.
Jaskaran Singh Saluja is a math wizard with nearly three years of experience as a math teacher. His expertise is in algebra, so he can make algebra classes interesting by turning tricky equations into simple puzzles.
: He loves to play the quiz with kids through algebra to make kids love it.