Solving IVP using Variable Change u = ln(y)

In summary, to solve the IVP dy/dt = -y ln(y), y(1) = 2, you can use the variable change u = ln(y) to convert the differential equation into one in terms of u. Then, you can solve for u and substitute back in to find the solution for y.
  • #1
dm59
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Use the variable change u = ln(y) to solve the IVP dy/dt = -y ln(y), y(1) = 2?

We haven't covered this in class yet so I do not know where to even start.
 
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  • #2
dm59 said:
Use the variable change u = ln(y) to solve the IVP dy/dt = -y ln(y), y(1) = 2?

We haven't covered this in class yet so I do not know where to even start.

Well, you're given [tex] u(t)=ln(y(t)) [/tex], so why not calculate [tex]y(t)[/tex] in terms of [tex] u(t) [/tex] and then differentiate to get [tex] \frac{dy}{dt} [/tex] in terms of [tex] u(t) [/tex] and [tex] \frac{du}{dt} [/tex] and then substitute these into your differential equation to get a DE in terms of u instead of y. What do you get when you do this?
 

FAQ: Solving IVP using Variable Change u = ln(y)

1. What is a differential equation?

A differential equation is a mathematical equation that describes the relationship between an unknown function and its derivatives. It expresses how the rate of change of the function is related to the function itself.

2. What is an initial value problem (IVP)?

An initial value problem (IVP) is a type of differential equation that involves finding the solution to a differential equation that satisfies a given set of initial conditions. These initial conditions typically specify the value of the function and its derivatives at a specific point.

3. How do you solve a differential equation IVP?

The process for solving a differential equation IVP involves finding the general solution to the equation and then using the given initial conditions to determine the specific solution that satisfies those conditions. This can be done through various methods such as separation of variables, integrating factors, or using Laplace transforms.

4. What are some real-world applications of differential equations IVP?

Differential equations IVPs have many applications in the fields of physics, engineering, and biology. They are used to model and predict the behavior of systems that involve rates of change, such as population growth, heat transfer, and circuit analysis.

5. Is there a connection between differential equations and calculus?

Yes, differential equations are closely related to calculus. In fact, the study of differential equations is considered to be a branch of calculus. Differential equations involve derivatives, which are a fundamental concept in calculus, and many techniques used to solve differential equations involve integration, another key concept in calculus.

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