Math Problem Statement

Solve the differential equation with the given initial condition: y' = y^7 - e^{4t}y^7, y(0) = 1.

Solution

The given differential equation is:

y=y7e4ty7,y(0)=1y' = y^7 - e^{4t} y^7, \quad y(0) = 1

Step 1: Simplify the equation

Factor out y7y^7 on the right side:

y=y7(1e4t).y' = y^7 \left(1 - e^{4t}\right).

This is a separable differential equation.


Step 2: Rewrite in separable form

We can write:

dyy7=(1e4t)dt.\frac{dy}{y^7} = \left(1 - e^{4t}\right) \, dt.


Step 3: Integrate both sides

Left side:

y7dy=y66=16y6.\int y^{-7} \, dy = \frac{y^{-6}}{-6} = -\frac{1}{6y^6}.

Right side:

(1e4t)dt=te4t4+C,\int \left(1 - e^{4t}\right) \, dt = t - \frac{e^{4t}}{4} + C,

where CC is the constant of integration.


Step 4: Combine the results

We have:

16y6=te4t4+C.-\frac{1}{6y^6} = t - \frac{e^{4t}}{4} + C.


Step 5: Solve for yy

First, isolate y6y^6:

16y6=e4t4tC.\frac{1}{6y^6} = \frac{e^{4t}}{4} - t - C.

Then:

y6=64e4t24t24C.y^6 = \frac{6}{4e^{4t} - 24t - 24C}.

Taking the sixth root on both sides:

y(t)=(64e4t24t24C)16.y(t) = \left(\frac{6}{4e^{4t} - 24t - 24C}\right)^{\frac{1}{6}}.


Step 6: Apply the initial condition y(0)=1y(0) = 1

At t=0t = 0, we know that:

1=(64e024(0)24C)16=(6424C)16.1 = \left(\frac{6}{4e^{0} - 24(0) - 24C}\right)^{\frac{1}{6}} = \left(\frac{6}{4 - 24C}\right)^{\frac{1}{6}}.

Raising both sides to the 6th power:

6=424C.6 = 4 - 24C.

Solve for CC:

24C=2C=112.24C = -2 \quad \Rightarrow \quad C = -\frac{1}{12}.


Step 7: Final solution

Substitute C=112C = -\frac{1}{12} into the equation:

y(t)=(64e4t24t+2)16.y(t) = \left(\frac{6}{4e^{4t} - 24t + 2}\right)^{\frac{1}{6}}.


This is the solution to the differential equation.

Do you have any questions or would you like further clarification?


Here are five related questions:

  1. How do you determine if a differential equation is separable?
  2. What are other methods to solve non-separable differential equations?
  3. How does the initial condition affect the general solution?
  4. What happens if the initial condition is not specified?
  5. Can numerical methods be used to solve this problem?

Tip: When solving differential equations, always check if you can separate variables first—this often makes solving easier.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Differential Equations
Separation of Variables
Initial Conditions

Formulas

y' = y^7 - e^{4t}y^7
Separable form: dy/y^7 = (1 - e^{4t}) dt
Integration of y^{-7}: -1/6y^6
Integration of (1 - e^{4t}): t - e^{4t}/4 + C

Theorems

Initial Value Theorem
Separation of Variables

Suitable Grade Level

Undergraduate Mathematics