Integration by Parts using Tabular Approach
Let’s find the integral of xeˣ using the tabular method:
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- Choose Functions:
- u = x
- dv = eˣ dx
- Create a Table:
- Choose Functions:
For the table, alternate between differentiating u and integrating dv. Start by listing u, its successive derivatives, and dv, its successive integrals:
u | dv |
---|---|
x | eˣ |
1 | eˣ |
0 | eˣ |
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- Apply Signs and Multiply Diagonally:
Now, apply alternating signs down the table. Multiply the terms diagonally and add them up:
(+) × (xeˣ) + (-) × (eˣ) + (+) × (eˣ)
Here’s how the multiplication works:
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- First row: (+) × (xeˣ) = xeˣ
- Second row: (-) × (eˣ) = -eˣ
- Third row: (+) × (eˣ) = eˣ
- Final Result:
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The integral of xeˣ is:
∫ xeˣ dx = xeˣ – eˣ + C
where C is the constant of integration.