Differential Equation with an Initial condition

In summary: Good luck!In summary, the given differential equation is separable but can also be solved using the Bernoulli method. It can be rearranged into a first-order differential equation and solved using an integrating factor.
  • #1
Zinggy
12
0

Homework Statement


x(dy/dx) = 3y +x4cos(x), y(2pi)=0

Homework Equations


N/A

The Attempt at a Solution


I've tried a couple different ways to make this separable, but you always carry over a 1/dx or 1/dy term and I can never fully separate this. I've also tried to do a Bernoulli differential equation method by doing a change of variable and putting it in the form: xy'-3y = x4cos(x) but it's not quite the right format to allow that to work, I would need it to be y4cos(x) instead.
 
Physics news on Phys.org
  • #2
Hint: Integrating factors.
 
  • Like
Likes Zinggy
  • #3
Zinggy said:

Homework Statement


x(dy/dx) = 3y +x4cos(x), y(2pi)=0

Homework Equations


N/A

The Attempt at a Solution


I've tried a couple different ways to make this separable, but you always carry over a 1/dx or 1/dy term and I can never fully separate this. I've also tried to do a Bernoulli differential equation method by doing a change of variable and putting it in the form: xy'-3y = x4cos(x) but it's not quite the right format to allow that to work, I would need it to be y4cos(x) instead.
Divide both sides of the DE by ##x##. That gives a very standard first-order DE with a well-known solution. (Hint: the hint from #2).
 
  • Like
Likes Zinggy
  • #4
Divide both sides by ##x## and rearrange into:
##\dot y -\frac 3 x y = x^3 cos(x)##
Since you are studying differential equations I trust that you can figure out how to solve this.
 

1. What is a differential equation with an initial condition?

A differential equation with an initial condition is a mathematical equation that describes the relationship between a function and its derivatives. The initial condition specifies the value of the function at a specific point in the domain, usually denoted as the initial value or initial condition.

2. What is the purpose of an initial condition in a differential equation?

The initial condition serves as a starting point for solving the differential equation. It provides a known value for the function at a specific point, which helps to determine the solution for the entire domain.

3. How is an initial condition represented in a differential equation?

An initial condition is typically represented as a boundary condition, where the value of the function at a specific point is known. It is denoted as y(t0) = y0, where t0 is the initial time and y0 is the initial value of the function.

4. Can a differential equation have more than one initial condition?

No, a differential equation can only have one initial condition. This is because the initial condition specifies the value of the function at a specific point, and having multiple initial conditions would lead to conflicting values.

5. What is the role of an initial condition in solving a differential equation?

The initial condition plays a crucial role in determining the unique solution to a differential equation. It helps to narrow down the possible solutions and provides a starting point for solving the equation using various methods such as separation of variables, integrating factors, or Laplace transforms.

Similar threads

  • Calculus and Beyond Homework Help
Replies
25
Views
362
  • Calculus and Beyond Homework Help
Replies
8
Views
767
  • Calculus and Beyond Homework Help
Replies
6
Views
1K
  • Calculus and Beyond Homework Help
Replies
10
Views
484
  • Calculus and Beyond Homework Help
Replies
10
Views
1K
  • Calculus and Beyond Homework Help
Replies
5
Views
910
  • Calculus and Beyond Homework Help
Replies
0
Views
174
  • Calculus and Beyond Homework Help
Replies
1
Views
298
  • Calculus and Beyond Homework Help
Replies
2
Views
1K
  • Calculus and Beyond Homework Help
Replies
4
Views
1K
Back
Top