Approaching a Step Function Problem with Variation of Parameters

For 0<=t<10, you can let vs(t)=3t and solve for the particular solution, then add it to the homogeneous solution. Ultimately, you will have two solutions for each region and you can use the boundaries to determine the constants and join them smoothly. This approach should work for any step function vs(t). In summary, to solve the differential equation with a step function vs(t), find solutions in each region and join them smoothly at the boundaries.
  • #1
seto6
251
0

Homework Statement


Hello,

i have a small problem regarding this questions,

2w1tgfk.jpg


If the function vs(t) is a function for t>=0, i can solve thus no problem (we are required to solve using variation of parameters).

now i have a small problem, its not about how to solve it ,but how to approach this, it says let the vs(t) be a step function:

10mnc6w.jpg


now, do i just let vs(t)=3t for time 0<=t<10, and solve this, and just ignore the time before 0, and then calculate for 0<=t<10 and t=>10, then add up the solution ?

Homework Equations



n/a

The Attempt at a Solution


If i did it from 0<=t<10 and t>10
for t>10, its just a homogeneous second order equation, that means the answer would be Vo(t)=2(homogeneous solution)+(particular solution, due to 3t).

any hints on how can i approach this problem, thank you very much in advance.
 
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  • #2
Find solutions to the differential equation in each region and then join them smoothly at the boundaries. As you noted, for t>10, you have the homogeneous equation, so the solution in that region will be just the homogeneous solution.
 

1. What is a step function problem?

A step function problem is a mathematical problem that involves a function that changes abruptly at certain points, creating a "step" in the graph. These points are typically referred to as "jumps".

2. What is variation of parameters?

Variation of parameters is a method used to solve differential equations. It involves finding a specific solution by varying the parameters of the general solution, hence the name.

3. How does variation of parameters apply to step function problems?

In step function problems, the function may be discontinuous, making it difficult to find a general solution. Variation of parameters allows for the specific solution to be found by taking into account the jumps in the function.

4. What are the steps for approaching a step function problem with variation of parameters?

The steps for approaching a step function problem with variation of parameters are as follows:

  1. Identify the jumps in the function and label them as "before" and "after".
  2. Find the general solution for each section of the function.
  3. Use variation of parameters to find the specific solution for each section.
  4. Combine the specific solutions for each section to get the final solution for the entire function.

5. Are there any limitations to using variation of parameters for step function problems?

Yes, there are some limitations to using variation of parameters for step function problems. It may not be applicable for all types of step functions, and it may be more complicated to use with higher order differential equations. Additionally, the process can be time-consuming and may require a lot of calculations.

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