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 ▸

Write sin(4x) in terms of sin and cos.


Are we able to represent linear matrix transformations with complex numbers?


How do you calculate the derivative of cos inverse x?


If the complex number z = 5 + 4i, work out 1/z.