Solve the differential equation by variation of parameters: . Which of the following is the general solution?
Table of contents
- 0. Functions7h 52m
- Introduction to Functions16m
- Piecewise Functions10m
- Properties of Functions9m
- Common Functions1h 8m
- Transformations5m
- Combining Functions27m
- Exponent rules32m
- Exponential Functions28m
- Logarithmic Functions24m
- Properties of Logarithms34m
- Exponential & Logarithmic Equations35m
- Introduction to Trigonometric Functions38m
- Graphs of Trigonometric Functions44m
- Trigonometric Identities47m
- Inverse Trigonometric Functions48m
- 1. Limits and Continuity2h 2m
- 2. Intro to Derivatives1h 33m
- 3. Techniques of Differentiation3h 18m
- 4. Applications of Derivatives2h 38m
- 5. Graphical Applications of Derivatives6h 2m
- 6. Derivatives of Inverse, Exponential, & Logarithmic Functions2h 37m
- 7. Antiderivatives & Indefinite Integrals1h 26m
- 8. Definite Integrals4h 44m
- 9. Graphical Applications of Integrals2h 27m
- 10. Physics Applications of Integrals 3h 16m
- 11. Integrals of Inverse, Exponential, & Logarithmic Functions2h 34m
- 12. Techniques of Integration7h 39m
- 13. Intro to Differential Equations2h 55m
- 14. Sequences & Series5h 36m
- 15. Power Series2h 19m
- 16. Parametric Equations & Polar Coordinates7h 58m
13. Intro to Differential Equations
Basics of Differential Equations
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Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
Find the general solution of the differential equation .
A
B
C
D

1
Step 1: Rewrite the given differential equation in standard form. The given equation is (1 + x) * (dy/dx) - x * y = x + x^2. Divide through by (1 + x) (assuming 1 + x ≠ 0) to get dy/dx - (x / (1 + x)) * y = (x + x^2) / (1 + x).
Step 2: Recognize that this is a first-order linear differential equation of the form dy/dx + P(x) * y = Q(x), where P(x) = -x / (1 + x) and Q(x) = (x + x^2) / (1 + x).
Step 3: Find the integrating factor (IF). The integrating factor is given by e^(∫P(x) dx). Here, P(x) = -x / (1 + x). Compute the integral ∫(-x / (1 + x)) dx, which simplifies to -∫(x / (1 + x)) dx = -ln|1 + x|. Thus, the integrating factor is e^(-ln|1 + x|) = 1 / (1 + x).
Step 4: Multiply through the differential equation by the integrating factor (1 / (1 + x)) to make the left-hand side an exact derivative. This gives (1 / (1 + x)) * dy/dx - (x / (1 + x)^2) * y = (x + x^2) / (1 + x)^2. The left-hand side simplifies to d/dx [y / (1 + x)].
Step 5: Integrate both sides with respect to x. The left-hand side integrates to y / (1 + x), and the right-hand side requires integrating (x + x^2) / (1 + x)^2. Solve the integral on the right-hand side, and then multiply through by (1 + x) to isolate y. Add the constant of integration C to find the general solution.
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