Help evaluating another integral

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    Integral
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Homework Help Overview

The discussion revolves around the evaluation of the integral ∫e^2θ sin 3θ dθ, which falls under the subject area of integral calculus, specifically focusing on integration by parts (IBP).

Discussion Character

  • Exploratory, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the use of integration by parts, with attempts to define appropriate u and dv components. There are questions regarding the correctness of the chosen v in the second integration by parts attempt, and some participants express confusion over the notation and working presented.

Discussion Status

The discussion is ongoing, with participants providing guidance on the integration by parts method and questioning the accuracy of the calculations presented. There is an acknowledgment of the need to combine terms and resolve the integral, but no consensus has been reached on the correct approach or solution.

Contextual Notes

Some participants note difficulties in following the working presented, indicating potential errors in notation or setup. The original poster's attempts at integration by parts are under scrutiny, particularly concerning the handling of terms in the integral.

afcwestwarrior
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Homework Statement


∫e^2θ sin 3θ dθ


Homework Equations



∫u dv= uv- ∫v du

The Attempt at a Solution


u= e^2θ dv=sin 3θ dθ
du= 2* e^2θ v=(1/3) * - cos 3 θ

e^2θ 1/3) * - cos 3 θ - ∫1/3) * - cos 3θ 2* e^2θ dθ

what now
 
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Try another IBP (I think that should work)
 
∫1/3) * - cos 3θ 2* e^2θ dθ
u= cos 3θ dv= e^2θ
du= 3*sin 3θ v= e^2θ
cos 3θ e^2θ - ∫ e^2θ 3*sin 3θ
e^2θ 1/3) *(2/3) - cos 3 θ +cos 3θ e^2θ - ∫ e^2θ 3*sin 3θ
 
Integrate by parts once more. You will obtain another integral that is a multiple of the original one. Combine common terms (all the integrals on the left) and solve.
 
is my v correct for the second igb
 
ibp i mean
 
I'm having some trouble reading your working. I noticed a single "e^2θ 1/3)" term. You should not have any e^(2θ) without an accompanying cos or sin term. Check your working.
 

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