Find the solution the the differential equation d^2y/dx^2 + (3/2)dy/dx + y = 22e^(-4x)

We first find the complementary function by guessing y=e^(kx). Substituting this into the equation d^2y/dx^2 + (3/2)dy/dx + y = 0. we find k^2 + (3/2)k + 1 = 0 which factorises into (k+2)(k+1/2). So our complementary function is y= Ae^(-2x) + Be^(-x/2). Now we find any particular integral by guessing y = Le^(-4x). Substituting this in to the equation d^2y/dx^2 + (3/2)dy/dx + y = 22e^(-4x) we find that L(16e^(-4x) - 4e^(-4x) + e^(-4x)) = 22e^(-4x) and L=2. So the solution to the differential equation is y= Ae^(-2x) + Be^(-x/2) + 2e^(-4x) //

NE

Related Further Mathematics A Level answers

All answers ▸

How do you invert a 2x2 matrix?


Solve x^3=1 giving all the roots between -pi<=theta<=pi in exponential form


Sketch the curve y= ((3x+2)(x-3))/((x-2)(x+1)) and find values of y for which y>=3


How do you sketch the graph of y=(x-1)/(x+1)?