I have a horrible math teacher this year: she merely shows the steps to solving a problem and doesn't help us understand why and how it works.(adsbygoogle = window.adsbygoogle || []).push({});

1. The problem statement, all variables and given/known data

I need to find the equation for the height of a ferris wheel as it spins. It has a radius of 30m, and a center 18m above ground. It completes a cycle in 60s. The graph starts at the minimum

I think I can write these when the x axis is pi/2, pi, 2pi, etc. But now it's in seconds.

Max = 33m

min=3m

Amplitude is 15

Period is 60s

2. Relevant equations

y=AcosB(X-C)+D

3. The attempt at a solution

A=15

B= (cosine, so 2pi/60 or pi/30 ??????????)

C= (cosine, starting at min, so moved left or right over by 1/2 period so 30???

D= min is 3 meters above ground, so moved upwards period+3 , so 18??

y=15cos((pi/30)(X+30))+18

Now if my domain on my calculator is 0<x<60 and range 0<y<33 , then it looks good vertically, but it starts somewhere above 15 and not 3 ...not moved over enough.

My math teacher is horrible and doesn't explain anything...please help!

Edit: well that makes no sense. I graphed using an online calculator, and it worked fine. Then I tried on my calculator again and it was off. So I reset my calc. and tried again, and it worked. Is that still the correct answer ^ ?

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