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Let n>1 be a positive integer. show that the functional

1
S[y]=∫ (y’)ⁿeʸdx, y(0)=1, y(1)= A>1,
0
has a stationary path given by
y=nIn(cx+e¹/ⁿ),
where
c=eᴬ/ⁿ-e¹/ⁿ.
Use the Jacobi equation to determine the nature of this stationary path.

User JimSan
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1 Answer

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Final answer:

The question involves finding the stationary path of a given functional using the Euler-Lagrange equation and analyzing its stability with the Jacobi equation, within the context of the time-independent Schrödinger equation in quantum mechanics.

Step-by-step explanation:

The subject of the question is Physics, as it pertains to solving the time-independent Schrödinger equation, which is a fundamental concept in quantum mechanics. The question specifically involves finding a stationary path for a functional involving the derivative of a function raised to a power and multiplied by an exponential factor, a problem that is likely at the advanced undergraduate or graduate level in physics or applied mathematics courses.

To address the question provided, the Euler-Lagrange equation would be used to find the stationary paths for a given functional. For the functional 1S[y]=∫ (y’)ⁿn e⁵ dx with boundary conditions y(0)=1 and y(1)=A>1, you would take the functional derivative with respect to y and set it to zero to find the stationary paths. By integrating the resulting differential equation, you would arrive at the solution y=nIn(cx+e¹/ⁿn), where c is determined using the boundary conditions to be c=eᵄ/ⁿn-e¹/ⁿn.

The Jacobi equation, which is used to determine the stability of the stationary path, involves studying the second variation of the functional and checking the sign of the resulting expression when evaluated along the stationary path. By substituting the given stationary path into the Jacobi equation, you can assess whether the path corresponds to a minimum, maximum, or saddle point of the functional under small perturbations.

User Staros
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