Solve the following differential equation \(\displaystyle{y}{''}+{4}{y}={\cos{{x}}}{\sin{{x}}}\)

aidinacol7

aidinacol7

Answered question

2022-03-22

Solve the following differential equation
y+4y=cosxsinx

Answer & Explanation

Alannah Campos

Alannah Campos

Beginner2022-03-23Added 10 answers

The given equation is a second order linear, non-homogeneous differential equation with constant coefficient.
The general solution will be the sum of the complementary solution and particular solution.
The complementary solution for the given equation:
λ2+4=0
(λ2i)(λ+2i)=0
λ=2i, 2i
fow two complex root γ1qγ2 where γ1=α+iβ,
γ2=αiβ
y(x)=eαx(c1cos(βx)+c2sin(βx))
yc=c1cos(2x)+c2sin(2x)
The particular solution for the equation is
yp is of the form x(a1cos(2x)+a2sin2x)
a1cos(2x)+a2sin2x is Multiplies by x because
sin2x in the complementary solution computed2yp(x)dx2d2yp(x)dx2=d2dx2x(a1cos(2x)+a2sin2x)=4a1cos2x4a1sin(2x)+4a2cos(2x)4a2xsin(2x)
Solve further:
Substitute the Particular into the differential equation:
d2yp(x) dx 2+4yp(x)=12sin(2x)4a1xcos2x4a1sin(2x)+4a2cos(2x)4a2xsin2x+4{x(a1cos(2x)+a2sin2x)}12sin(2x);
4a1sin(2x)+4a2cos(2x)=12sin(2x)
Equate the coefficient of cos2x and sin2x;
4a1=12,4a2=0a1=18, a2=0
yp(x)=18xcos(2x)
Hence, the general solution for the given equation is:
y(x)=yc(x)+yp(x)
y(x)=c1cos(2x)+c2sin(2x)18xcos(2x)

Do you have a similar question?

Recalculate according to your conditions!

New Questions in Differential Equations

Ask your question.
Get an expert answer.

Let our experts help you. Answer in as fast as 15 minutes.

Didn't find what you were looking for?