ODE- not sure if this is correct

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The discussion centers on solving the differential equation (y*e^(2xy) + x) + [b*x*e^(2xy)] y' = 0, where the goal is to find the value of b that makes the equation exact. The user determined that b=1 and derived the expression (1/2)e^(2xy) + (x^2/2)e^(2xy) + h(y), concluding that h(y) is a constant c. However, the text's solution states e^(2xy) + x^2 = c, leading to a debate on whether multiplying the derived equation by 2 is valid, given that c is an arbitrary constant.

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The problem is :

(y*e^(2xy) +x) + [ b* x*e^(2xy) ] y' =0. Find b so the equation is exact and solve.

I found b=1 and worked the problem to (1/2)e^(2xy) + (x^2/2)e^(2xy) + h(y); where I found h(y) to be simply c.

The answer in the text states that e^(2xy) + x^2 =c

Would I be incorrect to multiply [ (1/2)e^(2xy) + (x^2/2)e^(2xy) = -c ] by 2 to arrive at the answer since c is an arbitrary constant?

Thanks
 
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newtomath said:
The problem is :

(y*e^(2xy) +x) + [ b* x*e^(2xy) ] y' =0. Find b so the equation is exact and solve.

I found b=1 and worked the problem to (1/2)e^(2xy) + (x^2/2)e^(2xy) + h(y); where I found h(y) to be simply c.

The answer in the text states that e^(2xy) + x^2 =c

Would I be incorrect to multiply [ (1/2)e^(2xy) + (x^2/2)e^(2xy) = -c ] by 2 to arrive at the answer since c is an arbitrary constant?

Thanks

I believe you are correct in multiplying through that way, absorbing the factor of 2 into the constant. However, it still will not give you the answer the text gives because you will now have e^(2xy)+x^2 e^(2xy)=c, where as the text gives e^(2xy)+x^2=c.
 
Thanks. My mistake, the second term is (x^2/2) , not (x^2/2)e^(2xy)
 

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