Solve the differential equation by separation of variables. 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
Struggling with Calculus?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
Solve the differential equation using the method of undetermined coefficients. Which of the following is the general solution?
A
B
C
D

1
Step 1: Identify the type of differential equation. The given equation y'' + 2y' = 2x + 7 - e^{-2x} is a second-order linear non-homogeneous differential equation. The method of undetermined coefficients is suitable for solving this type of equation.
Step 2: Solve the complementary (homogeneous) equation. The complementary equation is y'' + 2y' = 0. Solve this by finding the characteristic equation, which is r^2 + 2r = 0. Factorize to get r(r + 2) = 0, giving roots r = 0 and r = -2. Thus, the complementary solution is y_c(x) = C_1 + C_2 e^{-2x}, where C_1 and C_2 are constants.
Step 3: Determine the form of the particular solution. The non-homogeneous term on the right-hand side is 2x + 7 - e^{-2x}. Break this into two parts: a polynomial (2x + 7) and an exponential term (-e^{-2x}). For the polynomial, assume a particular solution of the form Ax^2 + Bx + C. For the exponential term, since e^{-2x} is already part of the complementary solution, multiply it by x to avoid duplication, resulting in a term of the form Dx e^{-2x}. Combine these to form the particular solution: y_p(x) = Ax^2 + Bx + C + Dx e^{-2x}.
Step 4: Substitute y_p(x) into the original equation. Compute y_p'(x) and y_p''(x), then substitute these along with y_p(x) into the differential equation y'' + 2y' = 2x + 7 - e^{-2x}. Collect like terms and equate coefficients of x^2, x, constant terms, and e^{-2x} to solve for A, B, C, and D.
Step 5: Combine the complementary and particular solutions. Once the coefficients A, B, C, and D are determined, the general solution is y(x) = y_c(x) + y_p(x). Substitute the values of A, B, C, and D into y_p(x) and add it to y_c(x) = C_1 + C_2 e^{-2x} to obtain the final general solution.
Watch next
Master Classifying Differential Equations with a bite sized video explanation from Patrick
Start learningRelated Videos
Related Practice
Multiple Choice
25
views
Basics of Differential Equations practice set
