Solving 2nd Order Differential Equation with Dirichlet BCs

In summary, the problem involves solving for the general solution of a quadratic equation with two different constants for two intervals, with no given boundary conditions. The solution requires finding two separate general solutions and setting them equal at the point of continuity to determine the constants.
  • #1
dirk_mec1
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Homework Statement


Solve:

[tex]
-D(x) \frac{d^2 T}{dx^2}=1
[/tex]

for [tex] x \in [0,1] [/tex]

D(x) =10-3 in [0,0.5] and D(x) = 1 in (0.5,1]

with homogeneous dirichlet boundary conditions

The Attempt at a Solution


So I have two quadratic equations with x(0)=x(1)=0 and continuity at x=0.5 but I'm missing a BC. I thought of the derative but I am uncertain. Can someone help me?
 
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  • #2
Missing a Boundary Condition? There are no boundary conditions given in the problem at all. You are asked for the general solution.

Solve for the general solution. T1(x), of [itex]d^2T/dx^2= -1000[/itex] between 0 and 0.5. That answer will involve two unknown constants, say C and D. Then solve for the general solution, T2(x), of [itex]d^2T/dx^2= -1 between 0.5 and 1. That will involve two new constants, say E and F. Set the values of the functions and their first derivatives equal at 0.5 in order to write E and F in terms of A and B. You should then have a two "piece" definition for T(x) both involving the same two constants, A and B.
 

FAQ: Solving 2nd Order Differential Equation with Dirichlet BCs

What is a 2nd Order Differential Equation?

A 2nd order differential equation is an equation that involves a function, its first derivative, and its second derivative. It is used to describe systems that involve acceleration, such as in physics and engineering.

What are Dirichlet Boundary Conditions?

Dirichlet boundary conditions are a type of boundary condition used in solving differential equations. They specify the values of a function at the boundary or edges of a domain, rather than the values of the function itself. In other words, they define the behavior of the function at the boundaries of a system.

Why is it important to solve 2nd Order Differential Equations with Dirichlet BCs?

Solving 2nd order differential equations with Dirichlet boundary conditions allows us to accurately model and predict the behavior of systems that involve acceleration. This is important in many fields such as physics, engineering, and economics.

What is the process for solving 2nd Order Differential Equations with Dirichlet BCs?

The process for solving 2nd order differential equations with Dirichlet boundary conditions involves first rearranging the equation into a standard form, then applying appropriate boundary conditions to find the constants of integration. This is followed by solving the resulting system of equations to find the solution to the original differential equation.

What are some real-life applications of solving 2nd Order Differential Equations with Dirichlet BCs?

There are many real-life applications of solving 2nd order differential equations with Dirichlet boundary conditions. Some examples include predicting the motion of a pendulum, modeling the vibrations of a guitar string, and determining the temperature distribution in a rod. These equations are also used in fields like economics to model population growth and in engineering to design structures that can withstand stress and strain.

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