- #1
EmmanuelD
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Bernoulli -- Find the general solution
Find the general solution of:
y'+xy=xy^3
Bernoulli's Equation
y'+xy=xy^3
(y^-3)y'+x(y^-2)=x
Let v=(y^-2), thus v'=((-2y^-3)y'
Then,
-v'/2+xv=x
Multiply through by (-2)
v'-2xv=-2x
Now it's in first-order linear so I multiply by e^int(-2x)dx = e^(-x^2)
(e^(-x^2))v'-2xe^(-x^2)=2xe^(-x^2)
This is where I'm getting stuck :(
BECAUSE: the integral of e^(-x^2) is the "error function?"
According to Wolfram, integral e^(-x^2) dx = 1/2 sqrt(pi) erf(x)+constant
----
Anyone get anything different or know where I might have messed up?
THANK YOU!
Homework Statement
Find the general solution of:
y'+xy=xy^3
Homework Equations
Bernoulli's Equation
The Attempt at a Solution
y'+xy=xy^3
(y^-3)y'+x(y^-2)=x
Let v=(y^-2), thus v'=((-2y^-3)y'
Then,
-v'/2+xv=x
Multiply through by (-2)
v'-2xv=-2x
Now it's in first-order linear so I multiply by e^int(-2x)dx = e^(-x^2)
(e^(-x^2))v'-2xe^(-x^2)=2xe^(-x^2)
This is where I'm getting stuck :(
BECAUSE: the integral of e^(-x^2) is the "error function?"
According to Wolfram, integral e^(-x^2) dx = 1/2 sqrt(pi) erf(x)+constant
----
Anyone get anything different or know where I might have messed up?
THANK YOU!