Deconstructing a Model

1 The four functions below are defined in the Hybrid CO2 Models Starter File. Use fit-model to fit periodic-cos and periodic-cos2 to the recent-table data.

fun periodic-cos(x): (4.13 * cos(6.28 * (x - 2023.35))) + 419.87 end
fun wave-cos(x):     (4.13 * cos(6.28 * (x - 2023.35)))          end
fun midline-cos(x):                                       419.87 end
fun periodic-cos2(x):     wave-cos(x)      +      midline-cos(x) end

2 Read these 4 functions carefully, and explain why periodic-cos2 will produce the same graph as periodic-cos.

Review: Other Models We’ve Seen

Linear

Quadratic

Exponential

Logarithmic

Sketch

Key Characteristics

What kind of model?

Scatter plot showing global CO2 levels over time, rising and falling in a general positive diagonal trend from January 2010 to December 2023

3 What do you Notice about this scatter plot? What do you Wonder?

4 Which of the other models you described above would make the most sense to fit to this scatter plot? Why?

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