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anonymous

  • one year ago

Please help me I will give you metals

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  1. anonymous
    • one year ago
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    @phi

  2. anonymous
    • one year ago
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  3. anonymous
    • one year ago
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    @dan815

  4. anonymous
    • one year ago
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    @robtony

  5. jim_thompson5910
    • one year ago
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    were you able to find dy/dx ?

  6. anonymous
    • one year ago
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    yes, I have the prime derivative I got -3x/y

  7. jim_thompson5910
    • one year ago
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    correct \[\Large \frac{dy}{dx} = \frac{-3x}{y}\]

  8. jim_thompson5910
    • one year ago
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    Now apply the derivative to both sides \[\Large \frac{dy}{dx} = \frac{-3x}{y}\] \[\Large \frac{d}{dx}\left[\frac{dy}{dx}\right] = \frac{d}{dx}\left[\frac{-3x}{y}\right]\] \[\Large \frac{d^2y}{dx^2} = ??\]

  9. anonymous
    • one year ago
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    and then for the y'' i got -3y-y'(-3x) --------- 4y^2

  10. anonymous
    • one year ago
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    and then I plug -3x/y on the y' right?

  11. jim_thompson5910
    • one year ago
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    correct and simplify

  12. anonymous
    • one year ago
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    -3y+(9x/y) ---------- 4y^2

  13. jim_thompson5910
    • one year ago
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    I'm not getting the same thing

  14. anonymous
    • one year ago
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    @jim_thompson5910 , from this pint do I just plug the values of x and Y?

  15. anonymous
    • one year ago
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    what did you get?

  16. anonymous
    • one year ago
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    |dw:1438995573413:dw|

  17. jim_thompson5910
    • one year ago
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    \[\Large \frac{d^2y}{dx^2} = \frac{-3y-(-3x)\frac{dy}{dx}}{y^2}\] \[\Large \frac{d^2y}{dx^2} = \frac{-3y+3x\left(\frac{-3x}{y}\right)}{y^2}\] \[\Large \frac{d^2y}{dx^2} = \frac{-3y-\frac{9x^2}{y}}{y^2}\] \[\Large \frac{d^2y}{dx^2} = \frac{-3y{\color{red}{*y}}-\frac{9x^2}{y}{\color{red}{*y}}}{y^2{\color{red}{*y}}}\] \[\Large \frac{d^2y}{dx^2} = \frac{-3y{\color{red}{*y}}-\frac{9x^2}{\cancel{y}}{\color{red}{*\cancel{y}}}}{y^2{\color{red}{*y}}}\] \[\Large \frac{d^2y}{dx^2} = \frac{-3y^2-9x^2}{y^3}\]

  18. anonymous
    • one year ago
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    oh I see you simplified it, and from here. Do I plug the x and y values into this derivate?

  19. jim_thompson5910
    • one year ago
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    yeah

  20. anonymous
    • one year ago
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    -2.625?

  21. jim_thompson5910
    • one year ago
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    yeah, -21/8 = -2.625

  22. anonymous
    • one year ago
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    okay, if they say that I need to put my answer into 2 decimal places, do i put -2.63?

  23. jim_thompson5910
    • one year ago
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    yes

  24. anonymous
    • one year ago
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    okay, thank you so much

  25. jim_thompson5910
    • one year ago
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    no problem

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