Wronskian and Linear Independence of y1 = t2 and y2 = t|t| in Second Order ODEs

In summary, the conversation discusses the Wronskian for two functions, y1 and y2, which are not linearly dependent over the interval [-1,1]. While the Wronskian is 0 for all t over this interval, it is not a conclusive test for linear independence. Stronger conditions, such as being analytic or normal solutions of a differential equation, may be needed for the test to be sufficient.
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For y1 = t2 and y2 = t|t| (y2'' is not defined at t = 0), the Wronskian is 0 for all t over the interval [-1,1]. However, the two functions are not linearly dependent over this interval in the sense that one is not a unique multiple of the other. Does this imply that the Wronskian tells linear independence only in a particular space that is specific to the solution set, in which the solution set to a second order ODE would be a 2-space?
 
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The Wronskian is not a conclusive test. That is when the Wronskian is identically zero we draw no conclusion. Often we impose stonger conditionns on the functions (like being analytic or normal solutions of a differential equation) so that the test becomes sufficient.
 
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What is a Wronskian?

A Wronskian is a mathematical tool used to determine the linear independence of a set of functions. It is represented by a determinant and is often used in differential equations.

Why is the Wronskian important?

The Wronskian is important because it helps us determine if a set of functions is linearly independent, which is crucial in solving certain problems in mathematics and physics. It also has applications in stability analysis and finding general solutions to differential equations.

How do I calculate the Wronskian?

To calculate the Wronskian, you need to first write the functions as a set of columns in a determinant. Then, take the first derivative of each function and write them in the next row of the determinant. Continue this process until you have a square matrix, and then solve for the determinant using standard methods.

What does a zero Wronskian mean?

If the Wronskian of a set of functions is equal to zero, it means that the functions are linearly dependent. This means that one of the functions can be written as a linear combination of the others. In other words, one function can be expressed as a multiple of another function.

Can the Wronskian be negative?

Yes, the Wronskian can be negative. The sign of the Wronskian does not affect its use in determining linear independence. It is the magnitude of the Wronskian that is important.

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