Easy differential equation question

In summary, the first equation has a solution of y''-4y'+4y=0 while the second equation requires a more restrictive first order ODE to eliminate the constant m in the solution y=mx+h/m.
  • #1
rock.freak667
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Homework Statement



Obtain the ordinary differential equations whose solution is
i)y=Ae2x+Bxe2x
ii)y=mx+ h/m where h is a constant and m is to be eliminated

Homework Equations





The Attempt at a Solution



For the first one it is simply:
y''-4y'+4y=0

For the second one it is just y''=0?
 
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  • #2
Not quite, y''=0 has a general solution y=Ax+B with no restrictions on A or B...you want an ODE that gives a more restrictive solution, one where A=m and B=(a constant)/m...so you need a more restrictive ODE...try a first order ODE instead of a second order one.
 
  • #3
But if I use a 1st order ODE, I won't eliminate the constant m
 

1. What is a differential equation?

A differential equation is an equation that relates a function to its derivatives. It is used to describe a relationship between a quantity and the rate of change of that quantity. It is commonly used in scientific and mathematical fields to model natural phenomena.

2. How do you solve a differential equation?

There are various techniques for solving differential equations, depending on the type of equation and its complexity. Some common methods include separation of variables, substitution, and using specific formulas for certain types of equations. It is important to have a good understanding of calculus and algebra to solve differential equations effectively.

3. What is an initial value problem?

An initial value problem is a type of differential equation that involves finding a function that satisfies both the equation and an initial condition. The initial condition usually specifies the value of the function at a certain point or the value of its derivative at that point. Solving an initial value problem involves finding the function that satisfies both the equation and the initial condition.

4. Can differential equations be solved analytically?

Some differential equations can be solved analytically, meaning that an exact solution can be found using mathematical techniques. However, not all equations have analytical solutions, and in some cases, numerical methods must be used to approximate a solution. Analytical solutions are often preferred as they provide a deeper understanding of the problem.

5. How are differential equations used in science?

Differential equations are used in various scientific fields, including physics, chemistry, biology, and engineering. They are used to model and understand complex systems and phenomena, such as population dynamics, chemical reactions, and the motion of objects. Differential equations are also essential in the development of mathematical models and simulations for predicting and analyzing real-world problems.

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