Integration By Tables

The Organic Chemistry Tutor
22 Mar 201812:40
EducationalLearning
32 Likes 10 Comments

TLDRThis video tutorial demonstrates the method of integration by tables, a technique used to find the indefinite integral of complex functions. It walks through three example problems, showing how to identify and apply the appropriate formula for each case, and emphasizes the importance of converting the integral expression from x to u variables. The video also highlights the need to adjust for differing values of du/dx when substituting variables and concludes with the final answers for each integral.

Takeaways
  • ๐Ÿ“š The video discusses finding the indefinite integral using integration by tables, a method for solving complex integrals.
  • ๐Ÿ” The first example is the integral of 1/(x^2) * โˆš(1-x^2), which requires identifying the correct formula from calculus resources.
  • ๐ŸŽฏ The formula used for the first example is โˆซ(1/u^2) * โˆš(a^2 - u^2) du = -1/(a^2u) * โˆš(a^2 - u^2) + C, where u = x and a = 1.
  • ๐ŸŒŸ The process involves substituting x with u and dx with du, and then applying the formula to find the integral.
  • ๐Ÿ“ˆ The second example is the integral of du/(u^2 * โˆš(u^2 + a^2)), with u^2 = 4x^2 and a^2 = 9, leading to u = 2x and du = 2dx.
  • ๐Ÿ”— In this case, the integral is transformed to match the formula, with adjustments for the u and a values, and dx is replaced with du/2.
  • ๐Ÿ“ The final result for the second example is -โˆš(9 + 4x^2)/ (9x) + C, after substituting the values of u and a into the formula.
  • ๐ŸŒ The third example is the integral of x^2/โˆš(5 - 4x^2), which also requires finding the appropriate formula from a calculus textbook or online resources.
  • ๐Ÿ”‘ The formula used for the third example is โˆซu^2/(โˆš(a^2 - u^2)) du = -u/(2โˆš(a^2 - u^2)) + (a^2/2) * arcsin(u/a) + C, with u = 2x and a = โˆš5.
  • ๐Ÿงฉ The integral is again transformed to match the formula, with the necessary substitutions and adjustments for the u and a values.
  • ๐Ÿ† The final result for the third example is (1/8) * (x * โˆš(5 - 4x^2) - 5 * arcsin(2x/โˆš5)) + C, after substituting and simplifying the expression.
Q & A
  • What is the main topic of the video?

    -The main topic of the video is how to find the indefinite integral using integration by tables.

  • What is the first example problem presented in the video?

    -The first example problem is finding the integral of 1 divided by x squared, times the square root of 1 minus x squared, dx.

  • What formula is needed to solve the first example problem?

    -The formula needed for the first example is the integral of 1 over u squared, times the square root of a squared minus u squared, du, which is equal to negative 1 over a squared u, times the square root of a squared minus u squared, plus c.

  • How is the expression converted to contain the u variable in the first example?

    -In the first example, x squared and u squared are the same, so u is equal to x and du is equal to dx.

  • What is the second example problem worked on in the video?

    -The second example problem is finding the indefinite integral of d u divided by u squared, times the square root of u squared plus a squared.

  • How are the values of u and a identified in the second example?

    -In the second example, u squared is 4x squared, so u is the square root of 4x squared which is 2x, and a squared is 9, so a is the square root of 9 which is 3.

  • What is the significance of the formula used in the second example?

    -The formula used in the second example helps to identify the values of u and a, and allows for the conversion of the integral expression from x variable to the u variable for application of the formula.

  • What is the third example problem discussed in the video?

    -The third example problem is finding the indefinite integral of x squared divided by the square root of 5 minus 4x squared.

  • How is the expression changed to contain the u variable in the third example?

    -In the third example, a 4 is placed in front of x squared to turn it into u squared, and dx is replaced with du divided by 2.

  • What is the final result of the third example problem?

    -The final result of the third example is 1/8 times the negative of the square root of 5 minus 4x squared, plus 16 times the arc sine of 2x divided by the square root of 5, plus c.

  • What is the key takeaway from the video regarding integration by tables?

    -The key takeaway is to identify the right formula and then convert the integral expression from the x variable to the u variable before applying the formula to find the indefinite integral.

Outlines
00:00
๐Ÿ“š Introduction to Integration by Tables

This paragraph introduces the concept of finding the indefinite integral using the method of integration by tables. It begins with an example problem, which is finding the integral of 1 divided by x squared, times the square root of 1 minus x squared, with respect to x (dx). The speaker explains the need to identify the appropriate formula, which can be found in a calculus textbook or online resources. The formula needed for this example is the integral of 1 over u squared, times the square root of a squared minus u squared, du. The explanation continues with the process of substituting x squared for u squared, and dx for du, to solve the integral. The final answer is given as negative square root of 1 minus x squared over x, plus a constant of integration, c.

05:02
๐Ÿ” Identifying Formulas and Substitution

In this paragraph, the focus is on identifying the correct formula for integration by tables and the process of substitution. The speaker presents another example, the integral of du divided by u squared, times the square root of u squared plus a squared. The speaker emphasizes the importance of identifying the values of u and a, and how to convert the integral expression from x variable to u variable. The example provided involves u squared as 4x squared and a squared as 9, leading to u as 2x and du as 2dx. The speaker then demonstrates how to apply the formula and solve for the integral, resulting in the final answer of negative square root of 9 plus 4x squared, divided by 9x, plus a constant of integration, c.

10:03
๐Ÿงฎ Solving Complex Integrals with u-Substitution

The paragraph discusses solving a more complex integral involving x squared divided by the square root of 5 minus 4x squared. The speaker guides through the process of finding the appropriate formula from the textbook, which is the integral of u squared divided by the square root of a squared minus u squared du. The speaker then explains how to identify u as 2x and a as the square root of five, and how to convert the integral expression to contain the u variable. The solution involves multiplying the top and bottom by 4 to get rid of the x squared and turn it into u squared. The final answer is derived by substituting the values of u and a into the formula, resulting in an expression involving the square root of five minus four x squared, and an arc sine term, plus a constant of integration, c.

Mindmap
Keywords
๐Ÿ’กIndefinite Integral
The indefinite integral is a fundamental concept in calculus that represents the reverse process of differentiation. It is used to find the original function from its derivative, up to a constant. In the video, the indefinite integral is the main focus as the process of finding it using integration by tables is explained through various examples.
๐Ÿ’กIntegration by Tables
Integration by tables is a technique used in calculus to find the indefinite integral of a given function by using a set of standard integral formulas. It involves identifying a suitable formula and then substituting parts of the original function into this formula to obtain the integral. The video demonstrates this method by walking through several integral problems and showing how to match them with the correct formulas.
๐Ÿ’กFormula
In the context of the video, a formula refers to a pre-determined mathematical relationship that can be used to calculate the indefinite integral of a function. These formulas are essential for performing integration by tables, as they provide a structured way to approach and solve integral problems. The video emphasizes the importance of identifying the appropriate formula for each example.
๐Ÿ’กVariable Substitution
Variable substitution is a technique used in calculus where one variable is replaced with another to simplify the expression and make it easier to work with. In the context of the video, this is crucial for converting the original integral into a form that matches the formula for integration by tables. By substituting the correct variables, the complex integral expressions are transformed into a form that can be solved using the known formulas.
๐Ÿ’กu and du
In the process of integration by tables, 'u' and 'du' are temporary variables introduced through variable substitution. 'u' represents a function of the original variable (often 'x'), and 'du' is the differential of 'u'. The video explains how to identify 'u' and 'du' for each problem and how to use them to convert the integral into a solvable form.
๐Ÿ’กConstant 'a'
In the context of the video, 'a' is a constant that appears in the formulas for integration by tables. It represents a specific value that is squared and used in the denominator of the radical or under the square root. The value of 'a' is determined by the specific problem being solved and is crucial for applying the correct formula.
๐Ÿ’กSquare Root
The square root is a mathematical operation that is used to find a value which, when multiplied by itself, will give the original number. In the context of the video, square roots are used in the integrand (the function being integrated) and are part of the formulas for integration by tables. The video demonstrates how to handle square roots in the process of integrating functions.
๐Ÿ’กDifferential 'dx'
The differential 'dx' represents an infinitesimally small change in the variable 'x'. In calculus, 'dx' is used to describe the input of a function as it changes. The video explains how to handle 'dx' when substituting variables and how it relates to 'du' in the process of integration by tables.
๐Ÿ’กArcsine Function
The arcsine function, often denoted as 'arcsin', is the inverse function of the sine function and returns the angle whose sine is a given value. In the context of the video, the arcsine function appears in one of the formulas for integration by tables, indicating that some integrals may require the use of inverse trigonometric functions to solve.
๐Ÿ’กConstant of Integration
The constant of integration, denoted as 'c', is an additive constant that is included in the result of an indefinite integral. It accounts for the fact that the original function could have had any constant term, and thus the integral does not have a unique solution. The video mentions 'plus c' in the final answers of the integrals, highlighting the necessity of including this constant in the solution.
Highlights

The video discusses finding the indefinite integral using integration by tables, a method for solving complex integrals.

The integral of 1/(x^2) * sqrt(1 - x^2) is used as an example to demonstrate the process.

The appropriate formula for the example is identified as integral(1/u^2) * sqrt(a^2 - u^2) du = -1/(a^2u) * sqrt(a^2 - u^2) + C.

The expression is converted into one containing the u variable, where x^2 = u^2 and u = x, d u = dx.

The final answer for the first example is -sqrt(1 - x^2)/x + C, showcasing the application of the formula.

The second example involves finding the integral of du/(u^2 * sqrt(u^2 + a^2)) with u^2 = 4x^2 and a^2 = 9.

For the second example, d u is not equal to dx, so the expression must be converted to incorporate 2x dx.

The integral is manipulated to match the formula by multiplying the top and bottom by four and replacing dx with du/2.

The final answer for the second example is -sqrt(9 + 4x^2)/ (9x) + C, demonstrating the method's effectiveness.

The third example involves the integral of x^2/sqrt(5 - 4x^2), using a different formula for integration by tables.

In the third example, a^2 is found to be 5, u is 2x, and du is 2dx, requiring a conversion of the expression.

The integral is transformed by multiplying the top and bottom by 4 and replacing dx with du/2.

The final answer for the third example is 1/8 * (x * sqrt(5 - 4x^2) - 5 * (2x/sqrt(5)) + C), illustrating the versatility of the method.

Integration by tables is a powerful technique for solving integrals that do not fit standard formulas.

The method requires identifying the correct formula, substituting variables, and applying the formula accurately.

The video emphasizes the importance of recognizing when d u does not equal dx and adjusting the expression accordingly.

The examples provided in the video demonstrate the step-by-step process of integration by tables, making it easier to understand and apply.

The video is a valuable resource for those learning calculus and seeking to understand the integration by tables method.

Transcripts
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