Math Is Fun Forum

LuisRodg

Real Member

Registered: 2007-10-23

Posts: 322

Help on a initial-value problem.

Im trying to do this initial-value problem in which I know what to do but I do get a step they do on the Solutions Manual.

Heres the problem

dy/dx=(x^2 - 1)/(x^2 + 1)
y(1) = (pi)/2

Now I know I have to take the integral of dy/dx but in order to take the integral in the Solutions Manual they rewrite dy/dx as:

dy/dx = 1 - (2/(x^2 + 1))

How does one go from the first dy/dx to the rewritten one?

Thanks.

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: Help on a initial-value problem.

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Why did the vector cross the road?
It wanted to be normal.