Define 2nd order linear homogenous/non-homogenous differential equations along with two

piarepm

piarepm

Answered question

2021-12-26

Define 2nd order linear homogenous/non-homogenous differential equations along with two examples?

Answer & Explanation

Lakisha Archer

Lakisha Archer

Beginner2021-12-27Added 39 answers

Step 1
Consider the second order differential equation of the form y+p(x)y+q(x)y=f(x) where p(x),q(x),f(x) are continuous functions .The equation is known as non homogeneous differential equation.
If f(x)=0, the equation becomes y+p(x)y+q(x)y=0
Homogeneous linear differential equations is of the type y+p(x)y+q(x)y=0 where p(x),q(x) are continuous functions .
The characteristic equation can be written as t2+pt+q=0
The general solution of the equation depends upon the roots of the characteristic equation.
1. If the roots are real and distinct then the solution of the differential equation is y=c1ek1x+c2ek2x where k1 and k2 are the roots of the characteristic equation. c1 and c2 are arbitrary constants.
2. If the roots are real and distinct then the solution of the differential equation is y(c1x+c2ek1)x where k1 is the repeated root of the characteristic equation. c1 and c2 are arbitrary constants.
3. If the roots are complex then the solution of the differential equation is y=eαx(c1cosβx+c2sinβx) where α+βi and αβi are the complex root of the characteristic equation. c1 and c2 are arbitrary constants.
Solution of Non homogenous differential equation is calculated as follows.
The solution of Non homogenous differential equation has two parts.
The solution is given by y=yc+yp
where yc is calculated the same way as in homogenous equation.
yp is the particular solution.
Step 2
example 1:
consider the differential equation y+36y=0
the characteristic equation is t2+25=0
solving the equation
t2=36
t=±6i
therefore, y=0±5i
the roots are complex
Therefore, the solution is y=e0x(c1cos5x+c2sin5x)
Simplify to get the solution y=(c1cos5x+c2sin5x) where c1 and c2 are arbitrary constants.
Step 3
Example 2:
consider the differential equation y2y3y=e2t
find the general solution for the equation y2y3y=0
the characteristic equation is t22t3=0
t22t3=0
Thomas White

Thomas White

Beginner2021-12-28Added 40 answers

Solution.
We will use the method of undetermined coefficients. The right side of the given equation is a linear function f(x)=ax+b. Therefore, we will look for a particular solution in the form
y1=Ax+B
Then the derivatives are
y1=A,y=0.
Substituting this in the differential equation gives:
0+A6(Ax+B)=36x,A6Ax6B=36x.
The last equation must be valid for all values of so the coefficients with the like powers of in the right and left sides must be identical:6A=36
A6B=0
We find from this system that A=6,B=1. As a result, the particular solution is written as
y1=6x1.
Now we find the general solution of the homogeneous differential equation. Calculate the roots of the auxiliary characteristic equation:
k2+k6=0,D=14(6)=25,k1,2=1±252=1±52=3,2.
Hence, the general solution of the related homogeneous equation is given by
y0(x)=C1e3x+C2e2x
Thus, the general solution of the initial nonhomogeneous equation is expressed by the formula
y=y0+y1=C1e3x+C2e2x6x1.
Vasquez

Vasquez

Expert2022-01-09Added 669 answers

Consider the second order differential equation of the form y''+p(x)y'+q(x)y=f(x) where p(x),q(x),f(x) are continuous functions .The equation is known as non homogeneous differential equation.
If f(x)=0, the equation becomes y''+p(x)y'+q(x)y=0
Homogeneous linear differential equations is of the type y''+p(x)y'+q(x)y=0 where p(x),q(x) are continuous functions .
The characteristic equation can be written as t2+pt+q=0
The general solution of the equation depends upon the roots of the characteristic equation.
1. If the roots are real and distinct then the solution of the differential equation is y=c1ek1x+c2ek2x where k1 and k2 are the roots of the characteristic equation. are arbitrary constants.
2. If the roots are real and distinct then the solution of the differential equation is y(c1x+c2ek1)x where k1 is the repeated root of the characteristic equation. c1 and c2 are arbitrary constants.
3. If the roots are complex then the solution of the differential equation is y=eαx(c1cosβx+c2sinβx) where α+βi and αβi are the complex root of the characteristic equation. c1 and c2 are arbitrary constants.
Solution of Non homogenous differential equation is calculated as follows.
The solution of Non homogenous differential equation has two parts.
The solution is given by y=yc+yp
where yc is calculated the same way as in homogenous equation.
yp is the particular solution.
consider the differential equation y+36y=0
the characteristic equation is t2+25=0
solving the equation
t2=36
t=±6i
therefore, y=0±5i
the roots are complex
Therefore, the solution is y=e0x(c1cos5x+c2sin5x)
Simplify to get the solution y=(c1cos5x+c2sin5x) where c1 and c2 are arbitrary constants.
consider the differential equation y"2y3y=e2t
find the general solution for the equation y2y3y=0
the characteristic equation is t22t3=0
t22t3=0
t23t+t3=0
t(t3)+1(t3)=0
(t+1)(t3)=0
The solution of the characteristic equation are t=-1,t=3S which are real and distinct.
Therefore, the solution the differential equation is y=c1e1t+c2e3t

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