Solve Series Solutions Homework Equations

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Homework Statement


1. Using series solution to solve dy/dx - y(x) = x where y(0) = -1. [y(x) = Σ ak x^k from 0 to infinity.
2 Find c0 and c1 in y(x) = c0 e^αx + c1 e^-αx so that y(x) = a0 cosh(αx) +(a1/α) sinh (αx)
3. Find the 2 independent solutions of x d2y/dx2 + 2 dy/dx +xy = 0 using the frobenius solution with r = 0, -1


Homework Equations





The Attempt at a Solution

 
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You seem to have left out "The attempt at a solution". Certainly no deep thinking is required. Find the first derivative of y= \sum_0^\infty a_k x^k and put those two series into dy/dx- y= x.
 
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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