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Math Help - Differential Equation:Confirm my answer

  1. #1
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    Differential Equation:Confirm my answer

    dy/dx + 0.2y =0.6e^ -(0.7x)

    For condition y(0)=10

    I get the following answer after applying the condition:
    Y = -0.3e^ -(0.7x) +10.3e^ -(0.2x)

    Can someone confirm if i have this correct ?

    thanks, Rossco
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  2. #2
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    I get:

    y=\frac{56}{5}e^{\frac{-x}{5}}-\frac{6}{5}e^{\frac{-7x}{10}}
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  3. #3
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    Quote Originally Posted by Rossco View Post
    dy/dx + 0.2y =0.6e^ -(0.7x)

    For condition y(0)=10

    I get the following answer after applying the condition:
    Y = -0.3e^ -(0.7x) +10.3e^ -(0.2x)

    Can someone confirm if i have this correct ?

    thanks, Rossco
    Quote Originally Posted by galactus View Post
    I get:

    y=\frac{56}{5}e^{\frac{-x}{5}}-\frac{6}{5}e^{\frac{-7x}{10}}
    Not that he needs confirmation from me, but galactus is correct.

    The easy way to check your work is to plug your solution into the differential equation. If it works, then you have the right solution. If it doesn't work, then you don't.

    Also, if this is a Math problem, it is better to use fractions.

    -Dan
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  4. #4
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    Thanks for the help so far.

    I have found some mistakes but still don't get Galactus's Answer.

    The Integrating factor is e ^(1/5x)

    Then i get Y = -3/5e^ (-3/10x) + Ce^(1/5x) this is before the condition to find C.
    This must be wrong but don't see what i've done wrong.Can you advise ?

    Rossco
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