In mathematics, functions are fundamental building blocks used to describe relationships between variables. A function can be defined as a rule or mapping that assigns exactly one output value to each input value. Functions can model various real-world situations, such as population gr...
Introduction
In mathematics, functions are fundamental building blocks used to describe relationships between variables. A function can be defined as a rule or mapping that assigns exactly one output value to each input value. Functions can model various real-world situations, such as population growth, temperature changes, or financial trends. One of the fundamental operations that can be performed on functions is addition. Adding functions combines the output values of two functions to form a new function, capturing the combined effect of both original functions.
Definition of Function Addition
The addition of functions involves creating a new function whose output value is the sum of the output values of two individual functions. Mathematically, if we have two functions and , their sum is denoted as:
This notation indicates that the value of the new function at any input is obtained by adding the corresponding values of and at .
Example of Function Addition
Suppose we have two functions:
The sum of these functions is:
Substitute the expressions for and :
Simplify:
Thus, the new function formed by the addition of and is:
Properties of Addition of Functions
1. Commutative Property
The addition of functions satisfies the commutative property, which means the order of addition does not matter:
2. Associative Property
Function addition also satisfies the associative property, meaning when adding three functions, the grouping of the functions does not affect the result:
3. Identity Function
If there is a function defined as (a constant zero function), adding this function to any function does not change the function:
4. Closure Property
The sum of two functions is always a function itself. If and are functions, then is also a function.
Graphical Interpretation
Graphically, the addition of functions can be visualized by adding the corresponding -coordinates of the graphs of and at each -value.
Suppose the graph of is a line and the graph of is a parabola. The graph of would combine the vertical displacements of both graphs at each point along the -axis. This new graph represents the sum function.
Real-World Applications of Function Addition
Economics: Combining revenue and cost functions to calculate profit.
Physics: Adding forces acting on an object to find the net force.
Engineering: Combining electrical signals to find the resultant signal.
Biology: Summing population growth rates from different sources.
Practice Problems
Given:
Find:
Given:
Find:
Conclusion
The addition of functions is a fundamental operation in mathematics that combines the effects of two functions to produce a new function. Understanding how to add functions and interpret their results is essential in various fields such as science, economics, and engineering. Mastering this concept lays the groundwork for more complex operations with functions, such as multiplication, division, and composition.
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Added: Mar 09, 2025
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Slide Content
ADDITION ON FUNCTION
LEARNING OBJECTIVES 1. define operations on functions 2. identify the different operations on functions. 3. perform addition, subtraction, multiplication, division, and composition of functions
Which symbol represents addition? A. B. C. D. WARM UP EXERCISES
ADDITION Symbol Meaning Explanation Example Adding or combining two or more numbers. 3 + 2 = 5 If you have 3 apples and you add 2 more apples, you have 5 apples in total.
ADDITION ON FUNCTION Let f and g be functions. Their sum, denoted by π + π, is the function denoted by (π + π)(π₯) = π(π₯) + π(π₯)
EXAMPLE 1. Given the functions: π(π₯) = π₯ + 5, π(π₯) = 2π₯ β 1, β(π₯) = 2 + 9π₯ β 5 Determine the following functions: a. (π + π)(π₯) b. (π + h)(π₯) c. (π + h)(π₯) Β
BOARDWORK Given f(x) = 2x β 4, g(x) = 3x + 9, find f + g (x).
SAVE FOR A CAUSE Thru inspiration instilled by their parents and realization brought by Covid-19 pandemic experience, Neah and Neoh , both Senior High School students decided to save money for a charity cause. Neah has a piggy bank with β±10.00 initial coins inside. She then decided to save β±5.00 daily out of her allowance. Meanwhile, Neoh who also has a piggy bank with β±5.00 initial coin inside decided to save β±3.00 daily.
SAVE FOR A CAUSE Given the above situation, answer the following questions: a. How much money will be saved by Neah and Neah after 30 days? after 365 days or 1 year? their combined savings for one year? b. Is the combined savings enough for a charity donation? Why? c. What values were manifested by the two senior high school students? d. Will you do the same thing these students did? What are the other ways that you can help less fortunate people? e. Do you agree with the statement of Pope John Paul II said that βNobody is so poor he has nothing to give, and nobody is so rich he has nothing to receive"? Justify your answer. f. What functions can represent the amount of their savings in terms of number of days?
ASSESSMENT Directions: Find (f + g)(x) using the two functions given in each number. 1. f(x) = 3x + 3 g(x) = -4x + 1 Β 2. f(x) = 5x + 1 g(x) = 3x β 2 Β 3. f(x) = 2x + 5 g(x) = 4x 2 + 2x β 2