Differential equation/Integration problem

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SUMMARY

The discussion centers on solving the differential equation \(\frac{\mathrm{arcsinh}(y)}{y}\frac{dy}{dx}=B\), where B is a constant. The user attempted to integrate the left-hand side (LHS) using Wolfram Alpha but encountered inaccuracies. They also explored first principles and standard integral tables without success. Ultimately, they found that numerical integration provided a more accurate solution than the expression generated by Wolfram Alpha, particularly for values of y where the function's behavior changes.

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  • Understanding of differential equations and variable separation
  • Familiarity with the inverse hyperbolic sine function, arcsinh
  • Knowledge of numerical integration techniques
  • Experience with integral calculus and standard integral tables
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  • Study the properties of the inverse hyperbolic sine function, arcsinh
  • Learn about numerical integration methods, such as Simpson's Rule and Trapezoidal Rule
  • Explore advanced integration techniques for functions involving arcsinh
  • Investigate the use of computational tools like Wolfram Alpha for verifying integral solutions
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Mathematicians, physics students, and engineers dealing with differential equations and numerical methods for integration will benefit from this discussion.

JulieK
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I have the following problem

\begin{equation}
\frac{\mathrm{arcsinh}\left(y\right)}{y}\frac{dy}{dx}=B\end{equation}where B is constant. To solve the problem I separated the
variables and obtained

\begin{equation}
\int\frac{\mathrm{arcsinh}\left(y\right)}{y}dy=B \int dx\end{equation}I used Wolfram alpha to integrate the LHS and obtained an expression
which did not work for some reason. To check this I tried to do this
from first principles but the attempts led to dead end. I also could
not find such an integral in standard integral tables. Can someone
suggest a solution method to the problem or show me how to integrate
the LHS from first principles or prove Wolfram is right or wrong.
 
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Apparently the solution for ## \int\frac{\mathrm{sinh^{-1}}\left(y\right)}{y}dy ## is a series.

For y2 < 1, the solution is (Integral 731.1 from H. B. Dwight, Tables of Integrals and Other Mathematical Data, Macmillan, NY, NY 1961.

##y - \frac{1}{2\cdot 3\cdot{3}} y^3 + \frac{1\cdot{3}}{2\cdot{4}\cdot{5}\cdot{5}} y^5 - \frac{1\cdot{3}\cdot{5}}{2\cdot{4}\cdot{6}\cdot{7}\cdot{7}} y^7 + . . .##

for a more general solution, let y = x/a, and for y > 1 or < 1 the solution is somewhat different with even exponents.
## \int\frac{\mathrm{sinh^{-1}}\left(y\right)}{y^m}dy ## can be solved analytical for some m, at least for m = 2, 3
 
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Thanks Astronuc for your useful remark!
I solved the problem by testing Wolfram numerically using numerical integration. I noticed that Wolfram expression produces large errors in some cases.
Replacing Wolfram expression with numerical integration I obtained almost perfect results.
 

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