Solving this Linear Differential Equation?

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The discussion revolves around solving the linear differential equation dy/dx + 18x^17y = x^18 using integrating factors. The user has derived a general solution but struggles with substituting the integral of e^(x^18) with a variable "I" as instructed. Suggestions include using integration by parts and clarifying the integration process. The user seeks guidance on how to express the solution without integral signs due to website constraints. The conversation emphasizes the need for proper substitution techniques in solving the integral.
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Homework Statement


Find the general solution to this differential equation:
\frac{dy}{dx}+18x^{17}y=x^{18}
Use the variable I for replacing \int e^{x^{18}} dx

2. The attempt at a solution
I've solved the differential equation using integrating factors and obtained the following result:
y=\frac{\int e^{x^{18}}x^{18} dx + C}{e^{x^{18}}}

My problem is using the variable I for replacing the \int e^{x^{{18}}} dx. How am I suppose to do this with x^{18} inside the integral?
 
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τheory said:

Homework Statement


Find the general solution to this differential equation:
\frac{dy}{dx}+18x^{17}y=x^{18}Use the variable I for replacing \int e^{x^{18}}\,dx

2. The attempt at a solution
I've solved the differential equation using integrating factors and obtained the following result:
y=\frac{\int e^{x^{18}}x^{18}\,dx + C}{e^{x^{18}}}My problem is using the variable I for replacing the \int e^{x^{18}}\,dx. How am I suppose to do this with x^18 inside the integral?
You can't. You want to integrate by parts now.
 
Are you familiar with the product rule?

(f*g)' = f'g + g'f

I am not following what you are doing at all...

You already got the integrating factor e^{x^18}, why do you have \int e^{x^18} dx?
 
Okay well I did try using integration by parts after I obtained the general solution, but didn't get far as I got this:
\int e^{x^{18}}x^{18}dx

u = x^{18}
du = 18x^{17} dx
dv = e^{x^{18}} dv
v = \int e^{x^{18}} dv

uv - \int v du

x^{18}\int e^{x^{18}} dv - \int[ \int e^{x^{18}} dv] 18x^{17} dx

At this point, how am I suppose to utilize the substitution of \int e^{x^{18}}dx with I? In other words, how do I input the general solution into the website without inputting integrals? Since the website doesn't recognize integral signs, which is why it's asking me to use I for every \int e^{x^{18}}dx I encounter.

To the flyingpig's question, I need to use the variable "I" because it says to do so in the online problem that I'm doing.
 
Try using u=x and dv=x^{17}e^{x^{18}}\,dx.
 
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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