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 April 16th, 2015, 03:17 AM #1 Member   Joined: Apr 2014 From: australia Posts: 68 Thanks: 32 Ode Hi, just want to check if i have obtained the correct answer for the question below: dy/dt = 4y (x^3 - 1/2); a) Find ODE solution subject to initial conditions y(1) = 3/e. b) Find y(-1) Ans (a) For the general solution i get, y = Ce^(x^4 - 2x) At initial condition y(1) = 3/e y =3e^(x^4 - 2x) Ans (b) 3e thanks in advance Thanks from Yury Stepanyants
April 16th, 2015, 03:33 AM   #2
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Quote:
 Originally Posted by harley05 Hi, just want to check if i have obtained the correct answer for the question below: dy/dt = 4y (x^3 - 1/2); a) Find ODE solution subject to initial conditions y(1) = 3/e. b) Find y(-1) Ans (a) For the general solution i get, y = Ce^(x^4 - 2x) At initial condition y(1) = 3/e y =3e^(x^4 - 2x) Ans (b) 3e thanks in advance
A question about your ODE: Is this supposed to be dy/dx = ... or is x a function of t as well?

-Dan

Edit: Yup. It's a typo. You have the correct solution, but look at y(-1) again. $\displaystyle y(-1) = 3 \cdot exp((-1)^4 - 2(-1)) = 3 \cdot exp(1 + 2) = 3e^3$.

-Dan

Last edited by topsquark; April 16th, 2015 at 03:38 AM.

 April 16th, 2015, 03:52 AM #3 Member   Joined: Apr 2014 From: australia Posts: 68 Thanks: 32 thanks, yes it was a typo as you noticed. thanks again. Thanks from Yury Stepanyants

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