WEBVTT
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Okay, so, uh, this problem gives us
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that GFT for someone has already been infected. The
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infectious. Ah, the path of Genesis Kerr would
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just be a 90% of the curve given an example
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. Five. Um so how it it said in
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part A it the same threshold. Concentration is required
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. So that threshold concentration was 12. 10.
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So we need to figure out when that threshold is
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reached. And so if we plot 0.9 times FFT
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And so I did negative zero point 90 times,
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t minus 21 times t plus one. Okay.
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And so in doing that, I found that my
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t value and that gives me 12 10. Now
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, this craft, each side of that equation,
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uh, my my ex, my T value would
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have Teoh equal 11.258 So it would happen somewhere on
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the 11th day. The infection sickness would start.
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Can somebody is, um, just for sake of
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keeping track 11 point to find me? That's that's
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party as opposed to the 10th day. An example
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. Five. Um, Barbie says p three is
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that point where the infectiousness began. So be I'm
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gonna dio if you look back to our chart.
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Um, it says infectiousness began on day between day
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10 and 11. So they put in 10.
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So we're just gonna plug in 11 into this function
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and said my P three is gonna be 11 and
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then the actual number that would give it for 11
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. Um, we would give us 11. 88
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concentration. So I'm gonna use that point for P
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three. Um and so we're looking for a similar
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slope to the slope. An example? Five.
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Let's go back to example. Five. That slope
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waas. Um, negative. 23. And so
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the equation of that line is just gonna be a
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y minus 11. 88 equals negative 23 times T
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, but money's X in this case minus 11.
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Okay, so we comply. We can plot that
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into a graphing calculator and see where it intersex.
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Um, so let's find out where that would be
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. So if we graph that on the same graph
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, Okay, we're gonna have a p for around
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days. 17. So be 17.377 Um, and
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so I'm just gonna go ahead and say my p
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for is gonna be at 17 for my ex Dykes
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. It'll be happening on day 17. And if
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I plugged that into my, um, original equation
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, that's gonna give me 1101.6, because now we
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have a P three and p four going from day
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11 today. 17 Barbie, What date is the
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infectious in this? And it would end on the
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17th day and part c compute the level of infectiousness
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, if you remember from example five. The level
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of infectiousness is the area between the curve and that
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line. So we have the equation for the line
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. So I'm just gonna go back in, figure
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out issues, the original equation instead of this point
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for p four. Okay, so we're gonna take
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the integral of GFT, which remember, is 90%
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of fft and we're gonna subtract our equation here of
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the line. We're gonna integrate that from 11 to
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17. So that's gonna be minus negative 23 x
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the negative 23 times. Negative 11 And then we're
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going Teoh 2 53 and they were going to add
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11. 88 to that. Be 14 41.
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Okay, that'll give us our level of infectiousness.
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So Let's just do that side. A lot of
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side work that goes into this. So, um
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, we're gonna have negative 0.9 times. They use
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the information from example. Three eso We have negative
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R t cubed. Ah, minus 20 squared.
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Um, minus two t. So I'm kind of
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doing this on the five using the example. Um
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, and they were gonna be adding 23 x.
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It's attracting 14. 41. Okay, so that's
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gonna give us negative 0.9 t. Cute. Uh
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, plus 18 t squared. Those 1.80 Actually,
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this is gonna be positive, Teoh, from our
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original equation. Okay, I'm gonna I feel like
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I'm losing some stuff, so I'm gonna go back
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and reevaluate what GFT is. Um, so I
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apologize for this. I just wanna make sure way
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get it right. Not like I'm losing some negatives
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and losing some numbers here. Eso GFT. If
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we go back up to the top, let's just
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get that done. Ah is equal to negative 0.90
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times T minus 21 times T plus one, which
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is no 0.90 times T squared, minus 21 t
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plus T minus 21. Okay, that's gonna be
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negative. 0.9 t times t squared finest 20 T
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minus 21 which in turn gives us negative 0.9 t
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cubed plus 18. T square, 0.9 comes 21
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is 18.9 was 18.90. Okay, there's fungi of
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tea. And they were going Teoh ad 23 t
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and take away 14. 41. Okay, so
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our final equation that were integrating from 11 to 17
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is negative. 0.9 t caved plus 18 t squared
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. 23 plus 18.9. It's 41.9 minus 14.
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41. DT, This is a polynomial. Also
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to integrate it. We're just gonna dio kind of
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the powerful. She just adding one teach exponents and
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dividing by that number. So we're gonna have Can
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I get a 0.9? It's about about four times
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teacher before, plus 60 cubed. That's just 18
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. About about three was 41.9. About about Teoh
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a T squared minus 14. 21 t. We're
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evaluating that from 11 to 17. Okay, so
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evaluating at 17 we're gonna get a value of negative
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17 2.125 Okay, we're gonna subtract what we get
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. 11 also be negative. Most of the negative
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6089.3 to 5. Is that level of infectiousness.
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It's just attractors. So we have negative. 17
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2.25. The 6089.3 to 5. The level of
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infectiousness is gonna be 4387 0.2. That's gonna be
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cells per milliner days today.