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Solution of diffrential equation 6\frac{dy}{dx} -2y =xy^4   is 

  • Option 1)  2+(x+1)y3=2cy3ex    
  • Option 2) 2-(x+1)y3=2cy3e-x   
  • Option 3)2+(x-1)y3=2cy3e-x    
  • Option 4)  2-(x+1)y3=2cy3e
 

Answers (1)

best_answer

As we have learned

Bernoulli's Equation -

\frac{1}{y^{n-1}}= v

\frac{1}{y^{n}}\frac{dy}{dx}= \frac{1}{\left ( 1-n \right )}\frac{dv}{dx}

- wherein

\frac{1}{y^{n}}\frac{dy}{dx}+\frac{p}{y^{n-1}}=Q

 

 

 Given equation can be written as 

 

\frac{dy}{dx} - 1/3 y = (x/6 ) y^4\Rightarrow 1/y^4 \frac{dy}{dx} - 1/3 y^3 = x/6

 

Let  1/y^3 = t \Rightarrow -3/y^4 \frac{dy}{dx} = \frac{dt}{dx}

 

 1/y^4 \frac{dy}{dx}= -1/3 \frac{dt }{dx}

 

(-1/3) \frac{dt}{dx} -t/3 = x/6 \Rightarrow \frac{dt}{dx}+ t = -x/2

 

IF  is   e^{\int 1dx }= e^x

 \Rightarrow e^x \frac{dt}{dx} + e^x = \frac{-xe^x}{2} \Rightarrow \frac{d}{dx}(te^x) = -1/2 xe^x

\Rightarrow \int {d}(te^x) + 1/2\int xe^x=C

\frac{e^x}{y^3} + 1/2 xe^x - e^x = C

\Rightarrow 2+ (x-1)y^3 = 2cy^3e^{-x}

 

 

 

 

 

 


Option 1)

2+ (x+1)y^3 = 2cy^3e^x

Option 2)

2- (x+1)y^3 = 2cy^3e^{-x}`

Option 3)

2+ y^3(x-1) = 2cy^3e^{-x}

Option 4)

2- (x+1)y^3 = 2cy^3e^x

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gaurav

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