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Consider the boundary value problem y′′+λy=0,y(0)=y(L)=0,L>0. Find all λ>0 such that the boundary value problem has a solution other than y(x)=0. What is the solution in this case?

User Ryechus
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Final answer:

To find all λ > 0 such that the boundary value problem has a solution other than y(x) = 0, we analyze the given second-order linear homogeneous differential equation with constant coefficients. The solution will be in the form y(x) = c1e^(√λx) + c2e^(-√λx), where c1 and c2 are constants.

Step-by-step explanation:

To find all λ > 0 such that the boundary value problem has a solution other than y(x) = 0, we start by considering the given problem:

y′′ + λy = 0, y(0) = y(L) = 0

This is a second-order linear homogeneous differential equation with constant coefficients. The characteristic equation is obtained by assuming the solution of the form y(x) = e^(rx), where r is a constant:

r^2 + λ = 0

Solving this equation, we find the roots:

r = ±√(−λ)

Since we want a non-trivial solution (other than y(x) = 0), we want the roots to be non-zero. Hence, we need −λ < 0, or in other words, λ > 0.

Therefore, all λ values greater than 0 will have solutions other than y(x) = 0. The solution in this case will be of the form:

y(x) = c1e^(√λx) + c2e^(−√λx), where c1 and c2 are constants.

User Sean McCauliff
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