Integration problem with e (check my work)

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The integration problem involves the expression 5e^(5x)sin(e^(5x))dx. The user initially factored out 5 and substituted u for e^(5x), leading to the integral of u*sin(u). After integrating, they expressed the result as sin(u) - u*cos(u) before substituting back for u. Ultimately, the user resolved their confusion shortly after posting, indicating they found the correct solution. The discussion highlights the process of substitution and integration in solving the problem.
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Homework Statement



(integrate)5e^(5x)*sin(e^(5x))dx

Homework Equations





The Attempt at a Solution



I factored 5 out of the integration and made u to be e^5x, and du to be 5e^5x, or (1/5)du=e^(5x)dx. Because of this, the 5 factored out of the equation canceled out with the (1/5), leaving (integrate)u*sin(u).

I integrated that, making sin(u)-u*cos(u) (I think) and pu the e^(5x)s back where the u's were. Am I right in doing this?
 
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\int{f'(x)\sin{f(x)} dx = -cos(f(x)) + C
 
Last edited:
Never mind. I figured it out like right after I posted. Sorry.
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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