Differential equations - solving initial value problem

DWill
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Homework Statement


Solve the given initial value problem and determine how the interval in which the solution exists depends on the initial value y0.

y' = -4t/y, y(0) = y0


Homework Equations





The Attempt at a Solution


I solved the DE and got to:

y = +/- sqrt(C - 4t^2)

Plugging in y_0 for y when t = 0, I get:

y = +/- sqrt( (y_0)^2 - 4t^2 )

I'm pretty sure this is the right, but how do I answer the last part of the question? Figuring out the how the interval depends on initial value? thanks
 
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DWill said:

Homework Statement


Solve the given initial value problem and determine how the interval in which the solution exists depends on the initial value y0.

y' = -4t/y, y(0) = y0


Homework Equations





The Attempt at a Solution


I solved the DE and got to:

y = +/- sqrt(C - 4t^2)

Plugging in y_0 for y when t = 0, I get:

y = +/- sqrt( (y_0)^2 - 4t^2 )

I'm pretty sure this is the right, but how do I answer the last part of the question? Figuring out the how the interval depends on initial value? thanks
Usually, unless stated otherwise, one would assume that the solution must be real-valued.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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