## anonymous one year ago Izzy's heartbeat rate was measured on an EKG machine. After conversion, the function produced could be modeled by a sine function, and the wave produced a maximum of 8, minimum of −2, and period of π. Which of the following functions could represent Izzy's EKG read-out?

f(x) = 5 sin 2x + 3 should be the answer when done...since all other ways cant match the read-out properly....

2. ybarrap

|dw:1444090107913:dw| We need amplitude, A and period, T: $$A\sin\frac{2\pi t}{T}$$ The amplitude goes from 8 to -2 so the max "swing" is 8 - (-2) = 10, the amplitude is 10/2 = 5 = A, half the "swing", and the period, T is $$\pi$$. Does this make sense?

3. ybarrap

|dw:1444090404140:dw|

4. anonymous

yes, thank you

5. ybarrap

Now, since we have a "swing" from 8 to -2, we need to shift the whole thing below the x axis, otherwise we swing from 5 to -5 according to this equation; so, we need to add 3 to this equation: $$A\sin\frac{2\pi t}{T} +3$$ This is because the smallest the sine term will be is -5 and adding 3 to this brings the function up to -2 and the max from 5 to 8. Make sense?

6. anonymous

mhm

7. anonymous

The surface area of an oil spill gets 125% larger every day, represented by the function s(x) = (1.25)x − 1. On the first day, it covered an area of 49 square meters. Which function would be used to find the area of the oil spill on the 33rd day? A) s(x) = 49(1.25)x − 1 B) s(x) = (1.25)49 − 1 C) s(x) = (1.25)x − 49 D) s(x) = 1.25(49)x − 1