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Sunday, July 27, 2014

Separation of Variables, 21

Category: Differential Equations

"Published in Vacaville, 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 sec x sec y as follows







Integrate both sides of the equation, we have  





Therefore, the general solution is

 

Saturday, July 26, 2014

Solving Equations - Homogeneous Functions, 14

Category: Differential Equations

"Published in Vacaville, 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 algebraic functions 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 = C³.

Therefore, the general solution is

 

Friday, July 25, 2014

Solving Equations - Homogeneous Functions, 13

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 algebraic functions 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 










But



Hence, the above equation becomes 






 
Therefore, the general solution is