Free counters!

Thursday, July 17, 2014

Solving Equations - Homogeneous Functions, 9

Category: Differential Equations

"Published in Newark, California, USA"

Find the general solution for


Solution:

Consider the given equation above 


Did you notice that the given equation cannot be solved by separation of variables? The first and second term are the combination of x and y in the group and there's no way that we can separate x and y.  

This type of differential equation is a homogeneous function. Let's consider this procedure in solving the given equation as follows  


Let


so that


Substitute the values of y and dy to the given equation, we have  









The resulting equation can now be separated by separation of variables as follows  
 




Integrate on both sides of the equation, we have 

  





Take the inverse natural logarithm on both sides of the equation, we have







But



Hence, the above equation becomes  





where D = C².

Therefore, the general solution is

 

Wednesday, July 16, 2014

Separation of Variables, 16

Category: Differential Equations

"Published in Newark, California, USA"

Find the general solution for 


Solution:

Consider the given equation above  


In order to separate dx and dy from other variables, divide both sides of the equation by (1 - x)y² as follows




Integrate both sides of the equation, we have  







Take the inverse natural logarithm on both sides of the equation, we have






Therefore, the general solution is

 

Tuesday, July 15, 2014

Variable Separation, 15

Category: Differential Equations

"Published in Newark, California, USA"

Find the general solution for


Solution:

Consider the given equation above 

  
In order to separate dx and dy from other variables, divide both sides of the equation by x3y3 as follows





Integrate both sides of the equation, we have 









where D = 2C.

Therefore, the general solution is