Amanita, let's break down the problem and solve it step by step.
Problem Understanding:
We are given the differential equation:
x3y′′′+x2y′′−2xy′+2y=2x4,x>0
We are told that x, x2, and 1/x are solutions to the homogeneous version (where the right side is 0). We are to find a particular solution to the nonhomogeneous equation.
Step-by-Step Solution Plan:
Step 1: Write the homogeneous equation.
Set the right side to zero:
x3y′′′+x2y′′−2xy′+2y=0
Step 2: Find the general solution to the homogeneous equation.
Since x, x2, and 1/x are solutions, the general solution to the homogeneous equation is:
yh=C1x+C2x2+C3x1
where C1,C2,C3 are constants.
Step 3: Find a particular solution to the nonhomogeneous equation.
The right side is 2x4. We look for a particular solution, yp, of the form Ax4 (since the right side is a polynomial and none of the homogeneous solutions are x4).
Step 4: Substitute yp=Ax4 into the original equation and solve for A.
We need to compute the derivatives:
- yp=Ax4
- yp′=4Ax3
- yp′′=12Ax2
- yp′′′=24Ax
Substitute these into the equation and solve for A.
Let's execute these steps.
Step 4 Calculations:
Substitute into the equation:
x3(24Ax)+x2(12Ax2)−2x(4Ax3)+2(Ax4)=2x4
Let's simplify each term:
- x3(24Ax)=24Ax4
- x2(12Ax2)=12Ax4
- −2x(4Ax3)=−8Ax4
- 2(Ax4)=2Ax4
Sum:
24Ax4+12Ax4−8Ax4+2Ax4=2x4
(24A+12A−8A+2A)x4=2x4
30Ax4=2x4
Now, solve for A:
30A=2
A=302=151
Step 5: Write the particular solution.
So, the particular solution is:
yp=151x4
Final Answer:
Amanita, the particular solution to the given differential equation is:
yp=151x4