How Do You Find an Antiderivative Using the Substitution Method?

In Monday’s class, student found many antiderivatives using the Substitution Method. The basic process is illustrated below for the antiderivative

\displaystyle \int{4{{\left( {{x}^{2}}-3 \right)}^{3}}\cdot 2x,dx}.

Let’s look at the basic steps.

  1. Choose the expression for u. This is generally the inside part of a composition in the integrand. Use the derivative to find an other expression for du.
  2. Match the integrand with u and du. All variables in the original integrand must change to u.
  3. Change the integrand so that it is written in terms of u.
  4. Work out the antiderivative in terms of u.
  5. Put in the expression for u so that the antiderivative is written in terms of the original variable.

Now let’s look at the examples carried out in class.

Problem 1

\displaystyle \int{{{\left( 3{{x}^{2}}+4 \right)}^{4}}\cdot 6x,dx}

Problem 2

\displaystyle \int{{{\left( 3{{x}^{2}}+4 \right)}^{3}}\cdot 4x,dx}

Problem 3

\displaystyle \int{{{\left( {{x}^{2}}-1 \right)}^{5}}\cdot x,dx}

Problem 4

\displaystyle \int{4{{\left( 2x+3 \right)}^{2}},dx}

Problem 5

\displaystyle \int \frac{2}{{{\left( 2m+1 \right)}^{3}}} dm

 

Problem 6

\displaystyle \int{\frac{3}{\sqrt{3u-5}},du}

Problem 7

\displaystyle \int{-4{{e}^{2p}},dp}

Problem 8

\displaystyle \int{5{{e}^{-0.3g}},dg}