Solving a Second Order Linear Differential Equation

In summary, The conversation is about a person seeking help with solving an equation. The equation is y'' -2y' +3y =0 with initial values of y(0)=-1 and y'(0)=(root 2) -1. The auxiliary equation is r^2 -2r +3 = 0 and the roots are in the form r=M \pm Ni. The conversation also discusses using the quadratic formula to find the values of R1 and R2, which are 1+i and 1-i.
  • #1
s7b
26
0
Hi,

I'm having problems solving this equation;

y'' -2y' +3y =0 y(0)=-1 , y'(0)=(root 2) -1

I found the auxiliary equation r^2 -2r +3 = 0
and since b^2 -4ac is less than zero this the case where r1 and r2 are complex numbers.

This is as far as I get without getting stuck.

Please help me out if you know this.
Thanks :)
 
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  • #2
For ay''+by'+cy=0

the auxiliary equation is ar2+br+c=0. If b2-4ac <0, such that the roots are in the form [itex]r=M \pm Ni[/itex]

then y=eMx(Acos(Nx)+Bsin(Nx))
 
  • #3
To find R1 and R2 do you just use the quadratic formula?

So r1= 1+i
and r2=1-i
 
  • #4
s7b said:
To find R1 and R2 do you just use the quadratic formula?

So r1= 1+i
and r2=1-i

yep..so [itex]r= 1 \pm i[/itex] i.e. M=1 and N=1
 

1. What is a second order linear differential equation?

A second order linear differential equation is a mathematical equation that describes a relationship between a function, its first derivative, and its second derivative. It has the general form y'' + p(x)y' + q(x)y = r(x), where y' and y'' represent the first and second derivatives of y with respect to x.

2. How is a second order linear differential equation solved?

A second order linear differential equation can be solved by using various methods such as the method of undetermined coefficients, the method of variation of parameters, or the method of Laplace transforms. These methods involve finding a particular solution and a complementary solution, which are then combined to form the general solution.

3. What is the importance of second order linear differential equations?

Second order linear differential equations are important in many fields of science and engineering as they can be used to model various physical phenomena such as motion, heat transfer, and electrical circuits. They also have applications in areas such as economics and population dynamics.

4. What are the initial conditions in a second order linear differential equation?

The initial conditions in a second order linear differential equation refer to the values of the dependent variable (y) and its first derivative (y') at a specific point. These values are usually given at the starting point of the problem and are used to determine the constants in the general solution.

5. Can second order linear differential equations have complex solutions?

Yes, second order linear differential equations can have complex solutions. This can happen when the coefficients in the equation are complex numbers. In such cases, the solution will involve complex exponential functions, which can be simplified to real-valued solutions using Euler's formula.

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