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krypton

i need help with number 3 a and b

  • one year ago
  • one year ago

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  1. krypton
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    • one year ago
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  2. krypton
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    pls help

    • one year ago
  3. ivanmlerner
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    The opposite of derivative is integration, so in a you need to integrate once and on b, twice. Since the indefinite integral (with no limits of integration) gives you an arbitrary constant that disapears when you derivate, you need a way to find that constant because any number would satisfy the derivative formula since it would disapear when you derivated, thats why they give you one value of the function you want to find. Is it too confusing the way I explained or you got it?

    • one year ago
  4. krypton
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    b was the confusing one,so am to integrate t-cosx 2twice?

    • one year ago
  5. ivanmlerner
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    Yes, because you are derivating twice, but then you get 2 arbitrary constants.

    • one year ago
  6. krypton
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    whats this for dy(0)/dx=2 what do i need it for?

    • one year ago
  7. krypton
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    my first integration i got tx-sin(x)+c

    • one year ago
  8. ivanmlerner
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    Your integration is fine and now you need to determine c, thats when you use dy(0)/dx=2, because by integrating once, you got dy/dx

    • one year ago
  9. krypton
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    so how do i use this dy(0)/dx=2?

    • one year ago
  10. ivanmlerner
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    tx-sin(x)+c=dy/dx so t*0-sin(0)+c=2 Do you understand that?

    • one year ago
  11. krypton
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    yeah

    • one year ago
  12. krypton
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    so what about the y(0)=-2?

    • one year ago
  13. ivanmlerner
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    you have dy/dx, but you want y, so you integrate again, and youll need this to find the other constant.

    • one year ago
  14. ivanmlerner
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    So, did you got the answer?

    • one year ago
  15. krypton
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    i will integrate this tx-sin(x)+c again?

    • one year ago
  16. ivanmlerner
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    yes

    • one year ago
  17. ivanmlerner
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    because it is equal to dy/dx, and you want y

    • one year ago
  18. krypton
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    i got (tx^2/2)+cos(x)+c

    • one year ago
  19. ivanmlerner
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    you forgot to sonsider the constant of the previous integration

    • one year ago
  20. ivanmlerner
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    There will be two constants in this case, because its the second derivative.

    • one year ago
  21. krypton
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    cx+tx^2/2+cos(x)+c?

    • one year ago
  22. ivanmlerner
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    Yep thats it, but keep in mind that the c's are different, and the first one you should already have it as a number

    • one year ago
  23. krypton
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    the 1st one is 2 right?

    • one year ago
  24. ivanmlerner
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    yes

    • one year ago
  25. krypton
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    ok thanks alot for your help :)

    • one year ago
  26. ivanmlerner
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    You are welcome

    • one year ago
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