Find the equation knowing its asymptote in the infinite

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Homework Statement
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Find all linear differential equations of first order that satisfy this property:

All solutions are asymptotic to the straight line y = 3 - x, when x -> infinity

First i began writing the general equation:

y' + g(x)*y = h(x)

I would say that when x-> infinity, our equations will tends to 3-x (will behave like) and the angular coefficient will tends to -1

so:

-1 + (3-x)*g(x) = h(x)
x-> infinity

But i am not sure if this is right
 
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Start from the most general y which satisfies your condition, and work backwards.

For example, take y(x) = 3 - x + u(x) and work out y' + g(x)y.
 
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Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
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