Lesson Example Discussion Quiz: Class Homework |
Step-4 |
Title: Integration |
Grade: 10-a Lesson: S2-L6 |
Explanation: Hello Students, time to practice and review the steps for the problem. |
Lesson Steps
Step | Type | Explanation | Answer |
---|---|---|---|
1 |
Problem |
Evaluate \$ \int (x^2 * e^x) dx\$. |
|
2 |
Step |
Let’s consider the integral as follows: |
\$ \int (x^2 * e^x) dx\$ |
3 |
Step |
Using the technique of integration by parts, we choose |
\$ u = x^2 and dv = e^x dx \$ |
4 |
Step |
This gives us |
\$ du = 2x dx \$ \$ v = \int e^x dx = e^x \$ |
5 |
Formula: |
Applying the integration by parts formula: |
\$ \int u dv = uv - \int v du \$ |
6 |
Step |
After simplifying the integral on the right-hand side, our expression becomes: |
\$ \int (x^2 * e^x) dx = x^2 * e^x - \int e^x * 2x dx \$ |
7 |
Step |
Let’s focus on the remaining integral. We can use integration by parts again |
\$ \int x * e^x dx \$ |
8 |
Step |
After applying the integration by parts formula again, simplify the resulting equation |
\$ \int u dv = uv - \int v du \$ |
9 |
Step |
If we take \$e^x\$ as a common factor, the equation becomes: |
\$ \int ( x * e^x) dx = e^x(x - 1) \$ |
10 |
Step |
Substituting this result back into our original equation: |
\$ \int (x^2 * e^x) dx = x^2 * e^x - 2x * e^x + 2 * e^x + C \$ |
11 |
Step |
So, the value of the integral \$ \int (x^2 * e^x) dx \$ is \$ x^2 * e^x - 2x * e^x + 2 * e^x + C \$, where C is the constant of integration. |
|
12 |
Choice.A |
Option A is incorrect as it subtracts \$2⋅e^x\$ instead of \$2x ⋅ e^x\$ and doesn’t integrate the term involving \$x^2\$ correctly |
\$ x^2 * e^x - 2 * e^x + 2 * e^x + C \$ |
13 |
Choice.B |
Option B is incorrect because it doesn’t integrate correctly and includes a constant term that shouldn’t be there in the integral |
\$ x^2 * e^x - 2x * e^x + 2 + C \$ |
14 |
Choice.C |
Option C is incorrect because it omits \$x^2 * e^x\$ in the integral and presents \$x^2\$ outside the integral, violating the integration-by-parts method |
\$ x^2 - 2x * e^x + 2 * e^x + C \$ |
15 |
Choice.D |
The correct derivative for the given function appears to have been accurately determined |
\$ x^2 * e^x - 2x * e^x + 2 * e^x + C \$ |
16 |
Answer |
Option |
D |
17 |
Sumup |
Can you summarize what you’ve understood in the above steps? |
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