Having troubles integrating e^(2x)sin(x)

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In summary, the conversation discusses how to integrate the expression \int e^{2x}sinx by parts, but the term e^{2x} does not go away and the integration process becomes complicated. The original question involves finding the integration factor for the differential equation (-e^xsinx+y)dx+dy = 0, and the person is seeking advice on how to integrate it. The expert suggests using the ILATE rule, which stands for Inverse Circular Function, Logarithmic Function, Algebraic Function, Trigonometric Function, and Exponential Function, in that order, to determine the first function to integrate.
  • #1
haXadecimal
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Hi, I have to integrate this:

[tex]
\int e^{2x}sinx
[/tex]

I've tried by parts, but [tex]e^{2x}[/tex] never goes away and [tex]sinx[/tex] just keeps going back and forth to [tex]cosx[/tex]. Is there some kind of substitution I should use? The original question was the differential:

[tex](-e^xsinx+y)dx+dy = 0[/tex]

and I'm trying to find the integration factor to solve for [tex]y[/tex], but I can't seem to figure out how to integrate it. Thanks!
 
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  • #2
for your first question,
proceed with the integration by parts ...
label the original integral as I and continue
at some stage, u will have,
I = e^x something + something - I (or something like that)
rearrange to find I.

-- AI
 
  • #3
To clarify, keep integrating by parts until you get your original integral. then move that integral to the other side of the equation and solve :D
 
  • #4
Hi

Use the ILATE rule which tells you which function to take as the first one. ILATE = Inverse Circular Function, Logarithmic Function, Algebraic Function, Trigonometric Function, Exponential Function (this is the order...the function appearing higher in the list should be taken as the first function).

Cheers
Vivek
 

FAQ: Having troubles integrating e^(2x)sin(x)

1. What is the general process for integrating e^(2x)sin(x)?

The general process for integrating e^(2x)sin(x) is to use integration by parts, where one part of the integral is e^(2x) and the other part is sin(x).

2. How do I choose which part to integrate and which part to differentiate?

In general, it is helpful to choose the part that becomes simpler after differentiation. In this case, e^(2x) becomes simpler while sin(x) remains unchanged, so e^(2x) will be the part to differentiate.

3. Can I use substitution instead of integration by parts?

While substitution may work for simpler trigonometric integrals, it is not as effective for integrating e^(2x)sin(x). Integration by parts is a more efficient method for this specific integral.

4. How do I handle the repeated use of integration by parts?

If the integral requires multiple rounds of integration by parts, it is important to keep track of the terms and use the integration by parts formula multiple times until all terms can be simplified and integrated. This may require multiple substitutions as well.

5. Is there a shortcut or trick for integrating e^(2x)sin(x)?

Unfortunately, there is no shortcut or trick for integrating e^(2x)sin(x). It requires following the standard process for integration by parts and may involve multiple rounds of integration by parts and substitution.

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