MHB First order linear differential Equation

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The discussion revolves around solving the first-order linear differential equation given by (x^2+1)y'-2xy=x^2+1 with the initial condition y(1)=π/2. The user initially divides the equation by (x^2+1) and attempts to find an integrating factor, leading to confusion regarding the simplification of the exponential function. After clarification on logarithmic properties, the correct expression for the integrating factor is established as e^{-ln(x^2+1)}=1/(x^2+1). This understanding allows the user to proceed with solving the differential equation effectively. The exchange highlights the importance of correctly applying logarithmic and exponential rules in differential equations.
Petrus
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Hello MHB,
$$(x^2+1)y'-2xy=x^2+1$$ if $$y(1)=\frac{\pi}{2}$$What I have done:
Divide evrything by $$x^2+1$$ and we got
$$y'-\frac{2xy}{x^2+1}=1$$
we got the integer factor as $$e^{^-\int\frac{2x}{x^2+1}}= e^{-ln(x^2+1)}$$
Now I get
$$(e^{-ln(x^2+1)}y)'=e^{-ln(x^2+1)}$$
and this lead me to something wrong, I am doing something wrong or?

Regards,
$$|\pi\rangle$$
 
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Try simplifying the expression first , remember logarithm and exponential are (inverse) ...
 
ZaidAlyafey said:
Try simplifying the expression first , remember logarithm and exponential are (inverse) ...
that means if I got right
$$e^{-ln(x^2+1)}=-x^2-1$$?

Regards,
$$|\pi\rangle$$
 
No , remember the rules of logarithm $$\log x^n = n\log x $$ .
 
ZaidAlyafey said:
No , remember the rules of logarithm $$\log x^n = n\log x $$ .
Ahhh I see now! $$e^{-ln(x^2+1)}=e^{ln((x^2+1)^{-1})}= \frac{1}{x^2+1}$$
Thanks a lot Zaid! I should be able to continue!:) Thanks for fast responed and taking your time!

Regards,
$$|\pi\rangle$$
 

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