Find the solution to the differential equation

Yaaaldi
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Homework Statement



Find the solution when x(1)=2
dx/dt = (x2 - 1) / t






The Attempt at a Solution




I got all the variables to separate sides:

1/(x2 - 1) dx = 1/t dt

However I don't know how to integrate the LHS to get the correct answer.

The answer book says:

x = (t2 + 3)/(3 - t2)

Is the answer in the book wrong? I don't know how to integrate 1/(x2 - 1) without using the trig identity which isn't in the answers..
 
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Do you know the method of integration by partial fractions? That is what you'll need for \int \frac{1}{x^{2} - 1 } dx. (You could also use a trig substitution, but that's a bit excessive here...)

You will also need to do some algebra because integrating your separated differential equation is going to give you t(x) , rather than x(t) .

EDIT: Came back to this to finish working it through. The book's answer is correct.
 
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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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