ODE- not sure if this is correct

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In summary, the problem is to find the value of b so that the given equation is exact and then solve it. The solution involves finding the value of h(y) and using it to arrive at the final answer, e^(2xy)+x^2=c. It is possible to multiply the equation by 2 to arrive at this answer, but the constant c will still be present.
  • #1
newtomath
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The problem is :

(y*e^(2xy) +x) + [ b* x*e^(2xy) ] y' =0. Find b so the equation is exact and solve.

I found b=1 and worked the problem to (1/2)e^(2xy) + (x^2/2)e^(2xy) + h(y); where I found h(y) to be simply c.

The answer in the text states that e^(2xy) + x^2 =c

Would I be incorrect to multiply [ (1/2)e^(2xy) + (x^2/2)e^(2xy) = -c ] by 2 to arrive at the answer since c is an arbitrary constant?

Thanks
 
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  • #2
newtomath said:
The problem is :

(y*e^(2xy) +x) + [ b* x*e^(2xy) ] y' =0. Find b so the equation is exact and solve.

I found b=1 and worked the problem to (1/2)e^(2xy) + (x^2/2)e^(2xy) + h(y); where I found h(y) to be simply c.

The answer in the text states that e^(2xy) + x^2 =c

Would I be incorrect to multiply [ (1/2)e^(2xy) + (x^2/2)e^(2xy) = -c ] by 2 to arrive at the answer since c is an arbitrary constant?

Thanks

I believe you are correct in multiplying through that way, absorbing the factor of 2 into the constant. However, it still will not give you the answer the text gives because you will now have e^(2xy)+x^2 e^(2xy)=c, where as the text gives e^(2xy)+x^2=c.
 
  • #3
Thanks. My mistake, the second term is (x^2/2) , not (x^2/2)e^(2xy)
 

1. What is ODE?

ODE stands for Ordinary Differential Equation. It is a mathematical equation that describes how a quantity changes over time, based on the rate at which the quantity is changing at any given moment.

2. How are ODEs used in science?

ODEs are used to model and understand the behavior of many natural phenomena, such as population growth, chemical reactions, and motion of objects. They are also used in engineering and other fields to solve problems and make predictions based on mathematical models.

3. What is the difference between ODEs and PDEs?

ODEs describe the behavior of a single, changing quantity over time, while PDEs (Partial Differential Equations) describe the behavior of multiple, changing quantities over time and space. In other words, ODEs typically deal with one independent variable, while PDEs deal with multiple independent variables.

4. What are some real-world examples of ODEs?

Some examples of ODEs in science include the logistic equation for population growth, the Newton's second law of motion for motion of objects, and the Lotka-Volterra equations for predator-prey dynamics. ODEs are also used in various fields of engineering, such as electrical circuits and control systems.

5. What are the methods for solving ODEs?

There are several methods for solving ODEs, including analytical methods (such as separation of variables and integrating factors) and numerical methods (such as Euler's method and Runge-Kutta methods). The method used depends on the specific form of the ODE and the level of accuracy required for the solution.

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