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hiramoby Group Title

Given xy=-9 find dy/dt when x = -7 and dx/dt=-7

  • one year ago
  • one year ago

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  1. hiramoby Group Title
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    • one year ago
  2. hiramoby Group Title
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    the answers are in the screen shot

    • one year ago
  3. hiramoby Group Title
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    are you still there?

    • one year ago
  4. hiramoby Group Title
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    >>>???

    • one year ago
  5. Australopithecus Group Title
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    dy/dt xy = -9 dy/dt xy = -9 xy' = -9 y' = 9/7

    • one year ago
  6. Australopithecus Group Title
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    dx/dt xy = - 9 yx' = - 9 y(-7) = - 9 y =-9/-7 y = 9/7

    • one year ago
  7. Australopithecus Group Title
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    I think this is right just using implicit differentiation

    • one year ago
  8. Australopithecus Group Title
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    and chain rule

    • one year ago
  9. Australopithecus Group Title
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    do you understand how I got my answer?

    • one year ago
  10. hiramoby Group Title
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    Thank you, help me with my other question please. Yes I did , i was stuck after implicit.. thought it could not be this easy

    • one year ago
  11. Australopithecus Group Title
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    ok send me a link to your next question

    • one year ago
  12. zepdrix Group Title
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    @Australopithecus I'm confused by what you did in your steps. When you took the derivative, did you remember to apply the product rule? :o

    • one year ago
  13. hiramoby Group Title
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    austra i sent you a mail

    • one year ago
  14. Australopithecus Group Title
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    I dont need to apply the product rule because we are taking the derivative in respect to t not in respect to y or x so they are treated as constants

    • one year ago
  15. Algebraic! Group Title
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    no lol.

    • one year ago
  16. zepdrix Group Title
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    No both are variables, unless you're taking a partial derivative, you need to apply the product rule.

    • one year ago
  17. Algebraic! Group Title
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    both are functions of time.

    • one year ago
  18. zepdrix Group Title
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    I did the steps using the product rule and I also came up with 9/7... so maybe just a little bit of luck XD lol

    • one year ago
  19. Australopithecus Group Title
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    oh I guess so :)

    • one year ago
  20. Algebraic! Group Title
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    d/dt( x*y=-9) = dx/dt*y + x*dy/dt =0 dy/dt = -dx/dt *y/x

    • one year ago
  21. Australopithecus Group Title
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    can you break down the steps clearer algebraic!

    • one year ago
  22. Algebraic! Group Title
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    it's just use of the product rule on x*y =-9 then solving algebraically for dy/dt

    • one year ago
  23. zepdrix Group Title
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    |dw:1351050464937:dw| Leibniz notation (with the differentials) can be a little tricky to understand. Maybe if you see it with the primes it'll make some sense :o

    • one year ago
  24. Australopithecus Group Title
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    yeah that makes a lot more sense seeing as I had to take the derivative on both sides of the equation and I kept getting 0 Thanks for the refresher

    • one year ago
  25. Algebraic! Group Title
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    you do take the derivative on both sides and you do 'get 0'

    • one year ago
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