Math Problem Statement

Find the general solution of the differential equation: y^(5) - 6y^(4) + 9y''' - 6y'' + 8y' = 0.

Solution

To solve the differential equation given in the image:

y(5)6y(4)+9y6y+8y=0y^{(5)} - 6y^{(4)} + 9y''' - 6y'' + 8y' = 0

we'll proceed as follows:

  1. Form the Characteristic Equation: For a linear differential equation of the form y(5)6y(4)+9y6y+8y=0y^{(5)} - 6y^{(4)} + 9y''' - 6y'' + 8y' = 0, the corresponding characteristic equation is: r56r4+9r36r2+8r=0r^5 - 6r^4 + 9r^3 - 6r^2 + 8r = 0

  2. Factor Out rr: We can factor out rr from the characteristic equation: r(r46r3+9r26r+8)=0r(r^4 - 6r^3 + 9r^2 - 6r + 8) = 0 This gives one root, r=0r = 0.

  3. Solve the Remaining Polynomial r46r3+9r26r+8=0r^4 - 6r^3 + 9r^2 - 6r + 8 = 0: We can try factoring or using the Rational Root Theorem to find other roots. In this case, we observe that it factors as: (r2)(r2)(r2)(r+2)=0(r - 2)(r - 2)(r - 2)(r + 2) = 0 or (r2)3(r+2)=0(r - 2)^3 (r + 2) = 0

    This gives the roots:

    • r=0r = 0
    • r=2r = 2 (with multiplicity 3)
    • r=2r = -2
  4. Write the General Solution: Based on these roots, we can write the general solution for y(t)y(t) as follows: y(t)=c1+c2e2t+c3te2t+c4t2e2t+c5e2ty(t) = c_1 + c_2 e^{2t} + c_3 t e^{2t} + c_4 t^2 e^{2t} + c_5 e^{-2t} where c1,c2,c3,c4,c_1, c_2, c_3, c_4, and c5c_5 are arbitrary constants.

Final Answer:

y(t)=c1+c2e2t+c3te2t+c4t2e2t+c5e2ty(t) = c_1 + c_2 e^{2t} + c_3 t e^{2t} + c_4 t^2 e^{2t} + c_5 e^{-2t}

Would you like a detailed breakdown of each step or have any questions?


Related Questions

  1. How would you find the characteristic equation for a second-order linear differential equation?
  2. What is the significance of the multiplicity of roots in the characteristic equation?
  3. How does the presence of a zero root affect the solution of a differential equation?
  4. How would you solve a differential equation if complex roots were present?
  5. What methods can be used to factor higher-degree polynomials?

Tip:

Remember, the multiplicity of a root in the characteristic equation affects the solution's form by introducing polynomial terms in tt (e.g., tt, t2t^2) for each repeated root.

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Math Problem Analysis

Mathematical Concepts

Differential Equations
Characteristic Equations
Roots and Multiplicity

Formulas

Characteristic equation for nth-order differential equations

Theorems

Theory of linear differential equations
Root multiplicity in characteristic equations

Suitable Grade Level

College level