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Multiple Choice
Consider the initial value problem: , with and . What is the particular solution ?
A
B
C
D
Verified step by step guidance
1
Step 1: Recognize that this is a second-order linear differential equation with constant coefficients. The equation is y'' + 16y = cos(4t), and we are tasked with finding the particular solution y(t). The initial conditions are y(0) = 0 and y'(0) = 0.
Step 2: Solve the homogeneous equation y'' + 16y = 0. The characteristic equation is r^2 + 16 = 0, which has roots r = ±4i. This implies the general solution to the homogeneous equation is y_h(t) = C_1 cos(4t) + C_2 sin(4t).
Step 3: To find the particular solution y_p(t), use the method of undetermined coefficients. Since the right-hand side is cos(4t), propose a solution of the form y_p(t) = t(A cos(4t) + B sin(4t)). The factor of t is included because cos(4t) is a solution to the homogeneous equation.
Step 4: Substitute y_p(t) into the original differential equation y'' + 16y = cos(4t). Compute y_p'(t) and y_p''(t), then substitute these into the equation. Collect terms involving cos(4t) and sin(4t) to solve for the coefficients A and B.
Step 5: After determining A and B, combine the particular solution y_p(t) with the homogeneous solution y_h(t) to form the general solution. Apply the initial conditions y(0) = 0 and y'(0) = 0 to solve for the constants C_1 and C_2. The final particular solution is y(t) = (1/32)t sin(4t).