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itsonlycdeee

The equation below gives the height h of a passenger on a Ferris wheel at any time t during the ride to be h = 137 − 122 cos (π/10)t where h is given in feet and t is given in minutes. Use this equation to find the times at which a passenger will be 120 feet above the ground during the first revolution. I found the first time, which is about 4.5, but I'm confused on how to find the second time.

  • 9 months ago
  • 9 months ago

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  1. robz8
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    are you familiar with the unit circle? the are 2 quadrants in the unit circle which cos(t) is positive

    • 9 months ago
  2. itsonlycdeee
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    Yes, the 1st quadrant and the 4th quadrant.

    • 9 months ago
  3. robz8
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    is t inside or outside of the cos?

    • 9 months ago
  4. itsonlycdeee
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    Outside

    • 9 months ago
  5. primeralph
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    Should be inside.

    • 9 months ago
  6. primeralph
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    Well, most likely.

    • 9 months ago
  7. robz8
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    are you sure?, because then h = 137 − 122 cos (π/10)t would be linear, meaning there is only 1 time h = 120

    • 9 months ago
  8. itsonlycdeee
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    Oh, then inside does make more sense.

    • 9 months ago
  9. robz8
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    120 = 137 − 122 cos (π/10*t) -17 = -112 cos(π/10*t) 17/112 = cos(pi/10*t) \[\cos^{-1} (17/112) = \frac{ \pi }{ 10 }t\]

    • 9 months ago
  10. itsonlycdeee
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    Thank you I just figured it out!

    • 9 months ago
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