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causingaruckus,eh? Group Title

Find the norm of vector r prime of t when r(t) = t^2i + 2sintj + 2costk

  • one year ago
  • one year ago

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  1. modphysnoob Group Title
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    r'(t)=? r(t) is given

    • one year ago
  2. modphysnoob Group Title
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    so start with taking derivative

    • one year ago
  3. modphysnoob Group Title
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    then square each component , add them

    • one year ago
  4. modphysnoob Group Title
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    take square root

    • one year ago
  5. causingaruckus,eh? Group Title
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    \[\sqrt(4t^2 + 4\cos^2t + 4\sin^2t)\]

    • one year ago
  6. causingaruckus,eh? Group Title
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    What's the trig identity for cos and sin?

    • one year ago
  7. modphysnoob Group Title
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    cos^2 t + sin^2 t =1

    • one year ago
  8. causingaruckus,eh? Group Title
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    so does the second half of that just become 8?

    • one year ago
  9. modphysnoob Group Title
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    4( 1)=4

    • one year ago
  10. causingaruckus,eh? Group Title
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    Can you explain? I can never follow this one...

    • one year ago
  11. modphysnoob Group Title
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    cos(t)^2+sin(t)^2=1 4(cos(t)^2+sin(t)^2)=4

    • one year ago
  12. causingaruckus,eh? Group Title
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    Ohhhh.... Is that technically combining like terms?

    • one year ago
  13. modphysnoob Group Title
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    I guess

    • one year ago
  14. causingaruckus,eh? Group Title
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    Thanks!

    • one year ago
  15. modphysnoob Group Title
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    no problem

    • one year ago
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