Linear differential equations with constant coefficients - existence of solutions, Wronskian, independence of solutions, initial value problems for second-order equations - One Line Questions

1. What is the Wronskian of y1(x) = e^x and y2(x) = e^(-x)? -2
2. What is the Wronskian of y1(x) = x*e^x and y2(x) = e^x? 0
3. What is the Wronskian of y1(x) = cos(x) and y2(x) = sin(x)? 1
4. The existence and uniqueness theorem for a second-order linear differential equation ay'' + by' + cy = f(x) guarantees a unique solution when: a, b, c, and f(x) are continuous on an interval I, and a(x) != 0 on I, with given initial conditions y(x0) = y0 and y'(x0) = y1
5. What is a particular solution (yp) of ay'' + by' + cy = f(x)? Any one solution that satisfies the non-homogeneous equation
6. What is the characteristic equation associated with the differential equation ay'' + by' + cy = 0? ar^2 + br + c = 0
7. What is the general form of a second-order linear differential equation with constant coefficients? ay'' + by' + cy = f(x)
8. Applying the initial conditions y(0) = 2, y'(0) = 0 to y(x) = c1*e^x + c2*e^(-x) gives the system: c1 + c2 = 2, c1 - c2 = 0
9. Solving c1 + c2 = 2 and c1 - c2 = 0 yields: c1 = 1, c2 = 1
10. Solving the system c1 + c2 = 1 and c1 + 2c2 = 0 yields which values for c1 and c2? c1 = 2, c2 = -1
11. The existence and uniqueness theorem for second-order linear differential equations with constant coefficients requires the function f(x) to be: Continuous
12. The condition for a second-order linear differential equation with constant coefficients to have real, distinct roots in its characteristic equation depends on the: Discriminant of the characteristic quadratic equation (b^2 - 4ac)
13. If the roots of the characteristic equation are complex conjugates alpha ± i*beta, the functions e^((alpha+i*beta)x) and e^((alpha-i*beta)x) form a fundamental set of solutions. Which other pair also forms a fundamental set? e^(alpha*x)*cos(beta*x) and e^(alpha*x)*sin(beta*x)
14. If the characteristic equation has real roots r1 and r2, the functions e^(r1*x) and e^(r2*x) are solutions. If r1 = r2 = r, then the linearly independent solutions are: e^(r*x) and x*e^(r*x)
15. For the differential equation ay'' + by' + cy = f(x), what are 'a', 'b', and 'c' if the coefficients are constant? Constants
16. The concept of the Wronskian is primarily used to determine: Linear independence of solutions
17. If y1(x) and y2(x) are linearly independent solutions to a homogeneous linear differential equation, their Wronskian W(y1, y2)(x) is: Never zero
18. The Wronskian of the fundamental set of solutions {y1(x), y2(x)} for the homogeneous equation ay'' + by' + cy = 0 is: Non-zero for all x in the interval of definition
19. For an initial value problem y'' + p(x)y' + q(x)y = f(x) with y(x0) = y0 and y'(x0) = y1, a unique solution exists on an interval if: p(x), q(x), and f(x) are continuous on the interval and the coefficient of y'' is non-zero
20. What are the roots of the characteristic equation r^2 + 2r + 5 = 0? r = -1 ± 2i
21. What is the root of the characteristic equation r^2 + 4r + 4 = 0? r = -2 (repeated)
22. The roots of r^2 - 1 = 0 are: r = 1, r = -1
23. For the differential equation y'' - 3y' + 2y = 0, what are the roots of the characteristic equation r^2 - 3r + 2 = 0? r = 1, r = 2
24. For the equation y'' + y = 0, the characteristic equation is r^2 + 1 = 0. The roots are: r = i, r = -i
25. Consider the initial value problem: y'' - y = 0, y(0) = 2, y'(0) = 0. The characteristic equation is: r^2 - 1 = 0
26. Consider the initial value problem: y'' - 3y' + 2y = 0, with y(0) = 1 and y'(0) = 0. What is the characteristic equation? r^2 - 3r + 2 = 0
27. Consider the equation y'' + 2y' + 5y = 0. What is the characteristic equation? r^2 + 2r + 5 = 0
28. Consider the equation y'' + 4y' + 4y = 0. What is the characteristic equation? r^2 + 4r + 4 = 0
29. For a non-homogeneous linear differential equation ay'' + by' + cy = f(x), where f(x) is not identically zero, the general solution is the sum of: The complementary solution and a particular solution
30. What is the complementary solution (yc) of ay'' + by' + cy = f(x)? The general solution of the associated homogeneous equation ay'' + by' + cy = 0
31. If the Wronskian of two solutions y1(x) and y2(x) to a homogeneous linear differential equation is non-zero for at least one point in an interval, what can be concluded about these solutions? They are linearly independent
32. If y1(x) and y2(x) are linearly independent solutions to ay'' + by' + cy = 0, what is their Wronskian W(y1, y2)(x)? W(y1, y2)(x) != 0 for all x
33. If y1(x) and y2(x) are two solutions to ay'' + by' + cy = 0, and y1(x) is a non-trivial solution, then y2(x) is linearly dependent on y1(x) if and only if: y2(x) = k * y1(x) for some constant k
34. For the initial value problem y'' - 3y' + 2y = 0, y(0) = 1, y'(0) = 0, which of the following are the correct initial conditions to determine c1 and c2? y(0) = c1 + c2 = 1, y'(0) = c1 + 2c2 = 0
35. What is the general solution for y'' + 4y' + 4y = 0? y(x) = (c1 + c2*x)*e^(-2x)
36. If the characteristic equation ar^2 + br + c = 0 has one repeated real root r, what is the general solution to ay'' + by' + cy = 0? y(x) = (c1 + c2*x)*e^(r*x)
37. What is the specific solution to the initial value problem y'' - 3y' + 2y = 0, y(0) = 1, y'(0) = 0? y(x) = 2*e^x - e^(2x)
38. The general solution for y'' + y = 0 is: y(x) = c1*cos(x) + c2*sin(x)
39. If the characteristic equation ar^2 + br + c = 0 has two distinct real roots r1 and r2, what is the general solution to ay'' + by' + cy = 0? y(x) = c1*e^(r1*x) + c2*e^(r2*x)
40. The general solution for y'' - y = 0 is: y(x) = c1*e^x + c2*e^(-x)
41. What is the general solution for y'' - 3y' + 2y = 0? y(x) = c1*e^x + c2*e^(2x)
42. Consider the initial value problem: y'' + y = 0, y(0) = 1, y'(0) = 0. The specific solution is: y(x) = cos(x)
43. What is the general solution for y'' + 2y' + 5y = 0? y(x) = e^(-x) * (c1*cos(2x) + c2*sin(2x))
44. If the characteristic equation ar^2 + br + c = 0 has two complex conjugate roots alpha ± i*beta, what is the general solution to ay'' + by' + cy = 0? y(x) = e^(alpha*x) * (c1*cos(beta*x) + c2*sin(beta*x))
45. The specific solution to y'' - y = 0, y(0) = 2, y'(0) = 0 is: y(x) = e^x + e^(-x)
46. For the homogeneous equation ay'' + by' + cy = 0, if y1(x) and y2(x) are two solutions, and their Wronskian W(y1, y2)(x) = 0 for all x in an interval, what does this imply? y1 and y2 are linearly dependent
47. What is the Wronskian of two functions y1(x) and y2(x)? y1(x)y2'(x) - y1'(x)y2(x)