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WHAT IS THE DIFFERENTIAL EQUATION for tan(x^2+y^2)dy=xdx+ydy.?

WHAT IS THE DIFFERENTIAL EQUATION for tan(x^2+y^2)dy=xdx+ydy, does any body know?

what are the steps? I used the intergrating factor for the group term xdx+ydy, IF 1/(x^2+y^2). but my answer does not make sense. Anyone, please.

1 Answer

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  • ?
    Lv 6
    7 years ago
    Favorite Answer

    What an ugly question but easier than you think as

    tan[(x^2) + (y^2)] dy = x dx + y dy

    tan[(x^2) + (y^2)] = x dx/dy + y

    u = (x^2) + (y^2);

    du/dy = 2x * dx/dy + 2y

    1/2 * du/dy = x dx/dy + y

    tan(u) = 1/2 * du/dy

    1 = 1/2 * cot(u) * du/dy

    2 dy = cot(u) du

    2y + C = ln|sin(u)|

    2y + C = ln|sin((x^2) + (y^2))|

    C = ln|sin((x^2) + (y^2))| - 2y

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