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Tuesday, July 22, 2014

Solving Equations - Homogeneous Functions, 12

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





Next, we need to solve for the value of A, B, and C by partial fractions as follows 



Equate the coefficients of u², we have


Equate the coefficients for u, we have


Equate the coefficients for u⁰, we have


The value of B is equal to




Substitute the value of A, B, and C to the above equation, we have 








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




But



Hence, the above equation becomes







Therefore, the general solution is