Integrating Factor Differential Equation

In summary, the conversation is discussing how to solve the integral of \displaystyle\frac{x-2}{x(x-1)}\, through partial fraction decomposition. The person is having trouble solving the integral and is seeking help.
  • #1
Deathfish
86
0

Homework Statement



e∫^P(x)

∫[itex]\frac{x-2}{x(x-1)}[/itex]dx

The Attempt at a Solution



so i split it into

∫[itex]\frac{x-2}{x(x-1)}[/itex]dx
= ∫[itex]\frac{2x-1}{x^2-x}[/itex]dx - ∫[itex]\frac{x+1}{x^2-x}[/itex]dx

= ln(x2-x) - ∫[itex]\frac{x}{x^2-x}[/itex] - ∫(x2-x)-1

= ln(x2-x) - ln(x-1) - ∫(x2-x)-1

ok. having problems working out ∫(x2-x)-1dx
tried many ways but i keep ending up with the original integral.

u=x-1 --> du=-x-2
dv= (x-1)-1dx --> v=ln(x-1)

gives me ([itex]\frac{1}{x}[/itex])ln(x-1) + ∫[itex]\frac{ln(x-1)}{x^2}[/itex]dx

when i work this out

∫[itex]\frac{ln(x-1)}{x^2}[/itex]dx

u=ln(x-1) --> du=[itex]\frac{1}{x-1}[/itex]
dv=x-2dx --> v=-x-1

i get

∫[itex]\frac{ln(x-1)}{x^2}[/itex]dx = [itex]\frac{-ln(x-1)}{x}[/itex] + ∫(x2-x)-1

which is the same integral and above and i get no solution.
Need help...
 
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  • #2
Deathfish said:

Homework Statement



e∫^P(x)

∫[itex]\frac{x-2}{x(x-1)}[/itex]dx

...

Need help...
Use partial fraction decomposition on [itex]\displaystyle\frac{x-2}{x(x-1)}\,.[/itex]
 

What is an integrating factor?

An integrating factor is a function used to simplify the solution of a differential equation. It is multiplied to both sides of the equation to make it easier to solve.

Why do we use integrating factors?

We use integrating factors to solve differential equations that are not in a simple form, such as when they are not separable or linear.

How do you find the integrating factor for a differential equation?

To find the integrating factor, you first put the differential equation into standard form, then identify the coefficient of the highest order derivative. The integrating factor is then found by taking the exponential of the integral of this coefficient.

What is the role of an integrating factor in solving a differential equation?

The integrating factor helps to transform the original differential equation into a form that is easier to solve. It allows us to use techniques such as separation of variables or the method of undetermined coefficients to find the solution.

Can we use any function as an integrating factor?

No, the integrating factor must satisfy a specific condition to be effective in solving the differential equation. It must be a function that when multiplied to the original equation, it results in a new equation that can be easily solved.

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