Indefinite integral

🏆Practice domain of a function

An integral can be defined for all values (that is, for all X X ). An example of this type of function is the polynomial - which we will study in the coming years.

However, there are integrals that are not defined for all values (all X X ), since if we place certain X X or a certain range of values of X X we will receive an expression considered "invalid" in mathematics. The values of X X for which integration is undefined cause the discontinuity of a function.

integrals that are not defined for all values

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Test yourself on domain of a function!

\( 2x+\frac{6}{x}=18 \)

What is the domain of the above equation?

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  • An example of this is a function with a fraction with values X X in the denominator.
  • For example 1x1\over x
    According to mathematical rules, the denominator of a fraction cannot be zero since it is not possible to divide by zero. Therefore, when there is a possibility that the denominator equals zero, the integral cannot be defined for the values of X X that could cause the denominator to be zero.
Indefinite Integral
  • Another example is a square root function. For example
    According to the algebraic rules, the expression under the square root cannot be negative, that is, it must be positive or zero, but in no way negative. Therefore, The integral will be undefined for a range of values of X X that cause the expression under the square root to be negative.f(x)=x2x5f(x)=\sqrt{x^2-x-5}
Example of a negative square root function


Examples and exercises with solutions of indefinite integral

Exercise #1

2x+6x=18 2x+\frac{6}{x}=18

What is the domain of the above equation?

Video Solution

Step-by-Step Solution

To solve this problem and find the domain for the expression 2x+6x2x + \frac{6}{x}, we apply the following steps:

  • Step 1: Identify when the fraction 6x\frac{6}{x} is undefined. This occurs when the denominator xx equals zero.
  • Step 2: To find the restriction, set the denominator equal to zero: x=0x = 0.
  • Step 3: Solve for xx to find the values excluded from the domain. Here, x0x \neq 0.

Since 6x\frac{6}{x} is undefined for x=0x = 0, the value x=0x = 0 must be excluded from the domain.
Hence, the domain of the equation is all real numbers except zero.

Therefore, the solution to the problem, indicating the domain of the expression, is x0 x \neq 0 .

Answer

x≠0

Exercise #2

2x3=4x 2x-3=\frac{4}{x}

What is the domain of the exercise?

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Identify the fraction's denominator.

  • Step 2: Determine where this denominator equals zero.

  • Step 3: Exclude this value from the domain.

Now, let's work through each step:

Step 1: The given equation is 2x3=4x 2x - 3 = \frac{4}{x} . Notice that the fraction 4x\frac{4}{x} has a denominator of xx.

Step 2: Set the denominator equal to zero to determine where it is undefined.

x=0 \begin{aligned} x &= 0 \end{aligned}

Step 3: Since the expression is undefined at x=0x = 0, we must exclude this value from the domain.

Therefore, the domain of the expression is all real numbers except 0, formally stated as x0 x \neq 0 .

The correct solution to the problem is: x ≠ 0.

Answer

x≠0

Exercise #3

Look at the following function:

5x \frac{5}{x}

Does the function have a domain? If so, what is it?

Video Solution

Step-by-Step Solution

Since the unknown variable is in the denominator, we should remember that the denominator cannot be equal to 0.

In other words, x0 x\ne0

The domain of the function is all those values that, when substituted into the function, will make the function legal and defined.

The domain in this case will be all real numbers that are not equal to 0.

Answer

Yes, x0 x\ne0

Exercise #4

Look at the following function:

2x+202x10 \frac{2x+20}{\sqrt{2x-10}}

What is the domain of the function?

Video Solution

Step-by-Step Solution

To determine the domain of the function 2x+202x10 \frac{2x+20}{\sqrt{2x-10}} , we must ensure that the expression under the square root is non-negative, because the square root of a negative number is not defined in the real numbers.

We start by analyzing the denominator, specifically the square root, 2x10\sqrt{2x-10}. For the square root to be valid (for real numbers), we require:

  • 2x100 2x-10 \geq 0

Now, solve the inequality 2x1002x - 10 \geq 0:

  • Add 10 to both sides: 2x102x \geq 10
  • Divide both sides by 2: x5x \geq 5

However, since the expression 2x102x-10 also prohibits zero in the denominator (as the square root in the denominator cannot be zero), we strictly have:

  • x>5x > 5

Thus, the domain of the function is all xx such that x>5x > 5.

Therefore, the domain of the function 2x+202x10\frac{2x+20}{\sqrt{2x-10}} is x>5 x > 5 .

Answer

x>5 x > 5

Exercise #5

What is the domain of the exercise?

5x+82x6=30 \frac{5x+8}{2x-6}=30

Video Solution

Step-by-Step Solution

To find the domain of the expression 5x+82x6=30\frac{5x+8}{2x-6} = 30, we need to identify values of xx that make the denominator of the fraction zero.

Step 1: Identify the denominator of the fraction, which is 2x62x - 6.

Step 2: Set the denominator equal to zero to find the values to exclude:

  • Solve the equation 2x6=02x - 6 = 0.
  • Add 6 to both sides: 2x=62x = 6.
  • Divide both sides by 2: x=3x = 3.

Therefore, x=3x = 3 is the value that makes the denominator zero, so it must be excluded from the domain.

Given the choices, the correct answer is x3x \neq 3.

Therefore, the domain of the expression is all real numbers except x=3x = 3.

This implies that the correct choice is:

x3 x \neq 3

Answer

x≠3

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