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Last updated on September 14, 2025

Zero Function

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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.

Zero Function for US Students
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What is Zero Function?

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.
  
 

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What are the Characteristics of Zero Function

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.

  • The function can be written as y = 0. Since the output is said to be zero always, no matter what the input is, this graph is a horizontal line with a slope of 0. When comparing it with the slope-intercept form (y = mx + b), the slope (m) of the zero function is 0. 
  • Domain and range of zero function: Regardless of the number of elements in the domain, a zero function is a linear function with only one element in its range. The domain of the zero function is all real numbers R, and its range is  {0}, since it is defined for all values of x.
  • Derivative of zero function: Any constant function zero can be differentiated. We already know that the slope of the zero function is always zero, so the derivative is thought of as the function’s slope at any particular point. Therefore, the zero function’s derivative is zero.
  • Limit of zero function: The limit of a constant function is equal to the limit of the same constant, for all the properties of limits. As a result, the zero function’s limit equals 0.
  •  Continuity of zero function: The constant functions are said to be continuous because they represent the horizontal lines that run continuously and are uninterrupted on both sides. The zero function is continuous throughout the domain and has no breaks because it is said to be a constant function.
     
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Is Zero Function Even or Odd

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:

 

  • Graphical Method
  • Factorization Method
  • Quadratic Formula Method
  • Newton-Raphson Method
  • Bisection Method
  • Graphical Method

 

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.
 

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Real Life Applications of Zero Function

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.

  • Business break-even analysis
  • A business uses a function such as f(x)=revenue-cost to track its revenue and expenses. When f(x) = 0, the business is not turning a profit. This point, known as the break-even point, helps companies in determining pricing or production levels.
  • In physics, an object striking the ground
  • A quadratic function is used to model the height of an object that is thrown upward.  The time the object reaches the ground is given by setting the function to zero, that is, f(t) = 0. This helps in predicting the location and time of landing.
  • Engineering bridge design
  • Engineers use zero functions to find the points on a structure, like a beam or bridge, where the loads and the applied force are equal to zero. This helps in maintaining safety and balancing support structures. For example, the point of no deflection on a bridge might be represented by f(x) = 0.
  • Draining time of a water tank
  • A function can be used to express the amount of water left in a tank over time. The exact time that the tank will empty is provided by setting that function to zero. For example, if f(t)=-3t+30, solving f(t) = 0 gives the time when the tank is empty.
  • Monitoring loan repayment
  • To ascertain when a loan balance drops to zero following a sequence of payments, banks may employ a zero function. This makes it easier for the borrower and lender to monitor the payback schedule and period.
     
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Common Mistakes and How to Avoid Them in Zero Function

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.
 

Mistake 1

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The function is not set to zero.
 

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Keep in mind that, instead of factoring blindly, always set f(x)=0 to find zeros. For example, write: f(x)=x2-5x+6
So, the quadratic equation x2-5x+6=0.

Mistake 2

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Confusing zeros with the y-intercept
 

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Keep in mind that, while the y-intercept is the result when x = 0, zeros are the x-values for which f(x) = 0. For example, in f(x)=x2-5x+6. The zeros are x = 2, x = 3 and Y-intercept is f(0) = 6
 

Mistake 3

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Incorrect factoring
 

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Do not forget to check your factors. Students may write (x-2)(x-3), but:
(x-2)(x-3)=x2-5x+6 ≠ x2-6x+5
 The proper factorization is (x-5)(x-1)
 

Mistake 4

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Solving only one factor 
 

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Do not stop after resolving x - 3 = 0 if, f(x)=(x-3)(x-2). Additionally, resolve:
So, x = 3 and x = 2
 

Mistake 5

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Sign mistakes when solving
 

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Do not write x=-4 when solving x-4=0. The right answer is:
x = 4
Move terms carefully at all times.
 

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Solved Examples On Zero Function

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Problem 1

f(x)=x2-6x+5 find the zeros of the function

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f(x)=(x-5)(x-1)
 

Explanation

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.
 

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Problem 2

Find f(x)=3x-9

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3x-9=0
 

Explanation

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.
 

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Problem 3

Find f(x)=x2-9

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f(x)=(x-3)(x+3)
 

Explanation

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.
 

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Problem 4

Find f(x)=x(x+4)

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x(x+4)=0
 

Explanation

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.
 

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Problem 5

Zero of the function f(x)=2x2-8x. Find

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f(x)=2x(x-4)

Explanation

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.
 

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FAQs On Zero Function

1.What is a zero function?

 A zero function is a constant function that, regardless of the inputs, always results in zero as the output value.
 

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2.How is the zero function found?

To determine the intersection of the function’s graph and the y-intercept at point (a, 0).
 

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3.What is the conditional function for zero?

It is used to make statements about the real world, and often refers to general truths, such as scientific facts.
 

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4.What is the formula for 0?

The value of x where f(x) = 0 is found using the formula, which is as follows for quadratics: x=-b 土 b2-4ac2a
 

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5.Does zero function as a constant?

A zero function is a constant function where, for all values of x, f(x) = 0.
 

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Jaskaran Singh Saluja

About the Author

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.

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Fun Fact

: He loves to play the quiz with kids through algebra to make kids love it.

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