Constant Function

🏆Practice increasing and decreasing intervals of a function

We will say that a function is constant when, as the value of the independent variable X X increases, the dependent variable Y Y remains the same.

Let's assume we have two elements X X , which we will call X1 X1 and X2 X2 , where the following is true: X1<X2 X1<X2 , that is, X2 X2 is located to the right of X1 X1 .

  • When X1 X1 is placed in the domain, the value Y1 Y1 is obtained.
  • When X2 X2 is placed in the domain, the value Y2Y2 is obtained.


The function is constant when: X2>X1 X2>X1 and also \(Y2=Y1).

The function can be constant in intervals or throughout its domain.

Constant Function

Constant Function

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Test yourself on increasing and decreasing intervals of a function!

einstein

In what domain does the function increase?

–20–20–20–10–10–10101010202020–10–10–10101010000

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Constant Function Exercises

Exercise 1

Assignment

Find the decreasing and increasing area of the function

f(x)=5x225 f(x)=5x^2-25

Solution

In the first step, let's consider that a=5 a=5

Therefore a>0 a>0 and the parabola is at the minimum

In the second step, we find x x of the vertex

according to the data we know:

a=5,b=0,c=25 a=5,b=0,c=-25

We replace the data in the formula:

x=b2a x=\frac{-b}{2\cdot a}

x=025 x=\frac{-0}{2\cdot5}

x=010 x=\frac{-0}{10}

x=0 x=0

Answer

x<0 x<0 Decreasing

0<x 0<x Increasing


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Exercise 2

Assignment

Given the linear function of the graph

What is the domain of negativity of the function?

the function is always above the x-axis

Solution

Keep in mind that the function is always above the axis: x x

That is, the function is always positive and has no negative domain. Therefore, no x x

Answer

The function is always positive


Exercise 3

Assignment

Find the increasing area of the function

f(x)=6x212 f(x)=6x^2-12

Solution

In the first step, let's consider that a=6 a=6

Therefore a>0 a>0 and the parabola is a minimum

In the second step, we find x x of the vertex

according to the data we know that:

a=6,b=0,c=12 a=6,b=0,c=-12

We replace the data in the formula

x=b2a x=\frac{-b}{2\cdot a}

x=026 x=\frac{-0}{2\cdot6}

x=012 x=\frac{0}{12}

x=0 x=0

Therefore

0<x 0<x Increasing

x<0 x<0 Decreasing

Answer

0<x 0<x


Do you know what the answer is?

Exercise 4

Assignment

To find the increasing and decreasing area of the function, you need to find the intersection point of the vertex

Answer

True


Exercise 5

Assignment

Given the function in the diagram, what is its domain of positivity?

what is its domain of positivity

Solution

Note that the entire function is always above the axis: x x

Therefore, it will always be positive. Its area of positivity will be for all x x

Answer

For all x x


Check your understanding

examples with solutions for constant function

Exercise #1

Determine which domain corresponds to the function described below:

The function represents the amount of fuel in a car's tank according to the distance traveled by the car.

Step-by-Step Solution

According to the definition, the amount of fuel in the car's tank will always decrease, since during the trip the car consumes fuel in order to travel.

Therefore, the domain that is suitable for this function is - always decreasing.

Answer

Always decreasing

Exercise #2

Choose the graph that best describes the following:

The acceleration of a ball (Y) after throwing it from a building as a function of time (X).

Step-by-Step Solution

Since acceleration is dependent on time, it will be constant.

The force of gravity on Earth is constant, meaning the velocity of Earth's gravity is constant and therefore the graph will be straight.

The graph that appears in answer B satisfies this.

Answer

Weather101010Speed

Exercise #3

Choose the graph that best represents the following:

Temperature of lukewarm water (Y) after placing in the freezer as a function of time (X).

Step-by-Step Solution

Since the freezing point of water is below 0, the temperature of the water must drop below 0.

The graph in answer B describes a decreasing function and therefore this is the correct answer.

Answer

WeatherTemperature'000

Exercise #4

Determine whether the function is increasing, decreasing, or constant. For each function check your answers with a graph or table.

For each number, multiply by(1) (-1) .

Video Solution

Step-by-Step Solution

The function is:

f(x)=(1)x f(x)=(-1)x

Let's start by assuming that x equals 0:

f(0)=(1)×0=0 f(0)=(-1)\times0=0

Now let's assume that x equals minus 1:

f(1)=(1)×(1)=1 f(-1)=(-1)\times(-1)=1

Now let's assume that x equals 1:

f(1)=(1)×1=1 f(1)=(-1)\times1=-1

Now let's assume that x equals 2:

f(2)=(1)×2=2 f(2)=(-1)\times2=-2

Let's plot all the points on the function graph:

–5–5–5–4–4–4–3–3–3–2–2–2–1–1–1111222333444555666–3–3–3–2–2–2–1–1–1111222000

We can see that the function we got is a decreasing function.

Answer

Decreasing

Exercise #5

Determine whether the function is increasing, decreasing, or constant. For each function check your answers with a graph or table.

For each number, multiply by 0.

Video Solution

Step-by-Step Solution

The function is:

f(x)=x×0 f(x)=x\times0

Let's start by assuming that x equals 0:

f(0)=0×0=0 f(0)=0\times0=0

Now let's assume that x equals 1:

f(1)=1×0=0 f(1)=1\times0=0

Now let's assume that x equals -1:

f(1)=(1)×0=0 f(-1)=(-1)\times0=0

Now let's assume that x equals 2:

f(2)=2×0=0 f(2)=2\times0=0

Let's plot all the points on the function's graph:

–5–5–5–4–4–4–3–3–3–2–2–2–1–1–1111222333444555666–3–3–3–2–2–2–1–1–1111222000

We can see that the function we obtained is a constant function.

Answer

Constant

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