L2 Function Operations - Part 4
Completion requirements
Unit 1A
Precalculus
Lesson 2: Function Operations
The relationship between change in air temperature and altitude is directly proportional. Air temperature decreases as altitude «math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mi»h«/mi»«/mstyle»«/math»,
in metres, increases. This decrease in temperature continues until the tropopause, the boundary between the troposphere and the stratosphere in the Earth’s atmosphere, is reached. The tropopause is located at approximately «math style=¨font-family:Verdana¨
xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mrow»«mn»10«/mn»«mo»§#160;«/mo»«mn»000«/mn»«mo»§#160;«/mo»«mi mathvariant=¨normal¨»m«/mi»«/mrow»«/mstyle»«/math» above sea level. The drop in air temperature occurs at a rate of
«math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mrow»«mn»0«/mn»«mo».«/mo»«mn»6«/mn»«mo»§#160;«/mo»«mo»§#176;«/mo»«mi mathvariant=¨normal¨»C«/mi»«/mrow»«/mstyle»«/math» per «math style=¨font-family:Verdana¨
xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mn»300«/mn»«/mstyle»«/math» metres. Assume the temperature at sea level is «math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mn»20«/mn»«mo»§#160;«/mo»«mo»§#176;«/mo»«mi
mathvariant=¨normal¨»C«/mi»«/mstyle»«/math».
a.
Write a function that defines temperature at sea level as a function of altitude.
b.
Write a function that defines change in air temperature as a function of altitude below the tropopause.
c.
Write a function that could be used to predict the air temperature at any altitude below the tropopause.
d.
Graph the three functions.
a.
Let «math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mrow»«mi»f«/mi»«mfenced»«mi»h«/mi»«/mfenced»«/mrow»«/mstyle»«/math» be the temperature at sea level, in degrees Celsius. Since the
sea level temperature is independent of altitude, «math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mrow»«mi»f«/mi»«mfenced»«mi»h«/mi»«/mfenced»«mo»=«/mo»«mn»20«/mn»«/mrow»«/mstyle»«/math».
b.
Since the drop in temperature is directly proportional to altitude, it can be represented in the form «math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mrow»«mi»g«/mi»«mfenced»«mi»h«/mi»«/mfenced»«mo»=«/mo»«mi»k«/mi»«mi»h«/mi»«/mrow»«/mstyle»«/math»,
where «math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mrow»«mi»g«/mi»«mfenced»«mi»h«/mi»«/mfenced»«/mrow»«/mstyle»«/math» is the change in air temperature, in degrees Celsius, «math
style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mi»k«/mi»«/mstyle»«/math» is the rate of change of the air temperature, and «math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle
mathsize=¨14px¨»«mi»h«/mi»«/mstyle»«/math» is the altitude, in metres. Since the rate of change is known, «math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mrow»«mn»0«/mn»«mo».«/mo»«mn»6«/mn»«mo»§#160;«/mo»«mo»§#176;«/mo»«mi
mathvariant=¨normal¨»C«/mi»«mo»/«/mo»«mn»300«/mn»«mo»§#160;«/mo»«mi mathvariant=¨normal¨»m«/mi»«/mrow»«/mstyle»«/math», the value of «math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mi»k«/mi»«/mstyle»«/math»
can be calculated.
Therefore,
Since this function is only valid for altitudes below the troposphere, the restriction must be added to the function.
«math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mtable columnalign=¨right center left¨»«mtr»«mtd»«mi»g«/mi»«mi mathvariant=¨normal¨»(«/mi»«mi»h«/mi»«mi mathvariant=¨normal¨»)«/mi»«/mtd»«mtd»«mo»=«/mo»«/mtd»«mtd»«mi»k«/mi»«mi»h«/mi»«/mtd»«/mtr»«mtr»«mtd»«mo»§#8722;«/mo»«mn»0«/mn»«mi
mathvariant=¨normal¨».«/mi»«mn»6«/mn»«/mtd»«mtd»«mo»=«/mo»«/mtd»«mtd»«mi»k«/mi»«mfenced»«mn»300«/mn»«/mfenced»«/mtd»«/mtr»«mtr»«mtd»«mo»§#8722;«/mo»«mn»0«/mn»«mi mathvariant=¨normal¨».«/mi»«mn»002«/mn»«/mtd»«mtd»«mo»=«/mo»«/mtd»«mtd»«mi»k«/mi»«/mtd»«/mtr»«/mtable»«/mstyle»«/math»
Therefore,
«math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mrow»«mi»g«/mi»«mi mathvariant=¨normal¨»(«/mi»«mi»h«/mi»«mi mathvariant=¨normal¨»)«/mi»«mo»=«/mo»«mo»§#8722;«/mo»«mn»0«/mn»«mi mathvariant=¨normal¨».«/mi»«mn»002«/mn»«mi»h«/mi»«/mrow»«/mstyle»«/math».
Since this function is only valid for altitudes below the troposphere, the restriction must be added to the function.
«math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mrow»«mi»g«/mi»«mi mathvariant=¨normal¨»(«/mi»«mi»h«/mi»«mi mathvariant=¨normal¨»)«/mi»«mo»=«/mo»«mo»§#8722;«/mo»«mn»0«/mn»«mi mathvariant=¨normal¨».«/mi»«mn»002«/mn»«mi»h«/mi»«/mrow»«/mstyle»«/math»,
where «math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mrow»«mi»h«/mi»«mo»§#60;«/mo»«mn»1«/mn»«mspace width=¨0.125em¨/»«mn»0«/mn»«mo»§#160;«/mo»«mn»000«/mn»«/mrow»«/mstyle»«/math»
c.
The air temperature at a particular altitude, «math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mi»h«/mi»«/mstyle»«/math», is the temperature at sea level plus the temperature change
corresponding to that altitude.
Combine the previous two functions by addition to obtain a function that could be used to predict the air temperature at any altitude below the tropopause.
Combine the previous two functions by addition to obtain a function that could be used to predict the air temperature at any altitude below the tropopause.
«math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mtable columnalign=¨right center left¨»«mtr»«mtd»«mi»F«/mi»«mi mathvariant=¨normal¨»(«/mi»«mi»h«/mi»«mi mathvariant=¨normal¨»)«/mi»«/mtd»«mtd»«mo»=«/mo»«/mtd»«mtd»«mi»f«/mi»«mi
mathvariant=¨normal¨»(«/mi»«mi»h«/mi»«mi mathvariant=¨normal¨»)«/mi»«mo»+«/mo»«mi»g«/mi»«mi mathvariant=¨normal¨»(«/mi»«mi»h«/mi»«mi mathvariant=¨normal¨»)«/mi»«/mtd»«/mtr»«mtr»«mtd/»«mtd»«mo»=«/mo»«/mtd»«mtd»«mn»20«/mn»«mo»§#8722;«/mo»«mn»0«/mn»«mi
mathvariant=¨normal¨».«/mi»«mn»002«/mn»«mi»h«/mi»«mi mathvariant=¨normal¨»,«/mi»«mo»§#160;«/mo»«mi»h«/mi»«mo»§#60;«/mo»«mn»10«/mn»«mo»§#160;«/mo»«mn»000«/mn»«/mtd»«/mtr»«/mtable»«/mstyle»«/math»
d.

Using the information generated in Example 6, at what altitude will the temperature be «math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mrow»«mn»11«/mn»«mo»§#160;«/mo»«mo»§#176;«/mo»«mi mathvariant=¨normal¨»C«/mi»«/mrow»«/mstyle»«/math»?
The temperature will be «math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mrow»«mn»11«/mn»«mo»§#160;«/mo»«mo»§#176;«/mo»«mi mathvariant=¨normal¨»C«/mi»«/mrow»«/mstyle»«/math» at an altitude of «math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mrow»«mn»4«/mn»«mo»§#160;«/mo»«mn»500«/mn»«mo»§#160;«/mo»«mi mathvariant=¨normal¨»m«/mi»«/mrow»«/mstyle»«/math».
«math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mtable columnalign=¨right center left¨»«mtr»«mtd»«mi»F«/mi»«mi mathvariant=¨normal¨»(«/mi»«mi»h«/mi»«mi mathvariant=¨normal¨»)«/mi»«/mtd»«mtd»«mo»=«/mo»«/mtd»«mtd»«mn»20«/mn»«mo»§#8722;«/mo»«mn»0«/mn»«mi
mathvariant=¨normal¨».«/mi»«mn»002«/mn»«mi»h«/mi»«/mtd»«/mtr»«mtr»«mtd»«mn»11«/mn»«/mtd»«mtd»«mo»=«/mo»«/mtd»«mtd»«mn»20«/mn»«mo»§#8722;«/mo»«mn»0«/mn»«mi mathvariant=¨normal¨».«/mi»«mn»002«/mn»«mi»h«/mi»«/mtd»«/mtr»«mtr»«mtd»«mn»0«/mn»«mi
mathvariant=¨normal¨».«/mi»«mn»002«/mn»«mi»h«/mi»«/mtd»«mtd»«mo»=«/mo»«/mtd»«mtd»«mn»9«/mn»«/mtd»«/mtr»«mtr»«mtd»«mi»h«/mi»«/mtd»«mtd»«mo»=«/mo»«/mtd»«mtd»«mn»4«/mn»«mo»§#160;«/mo»«mn»500«/mn»«/mtd»«/mtr»«/mtable»«/mstyle»«/math»
The temperature will be «math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mrow»«mn»11«/mn»«mo»§#160;«/mo»«mo»§#176;«/mo»«mi mathvariant=¨normal¨»C«/mi»«/mrow»«/mstyle»«/math» at an altitude of «math style=¨font-family:Verdana¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mstyle mathsize=¨14px¨»«mrow»«mn»4«/mn»«mo»§#160;«/mo»«mn»500«/mn»«mo»§#160;«/mo»«mi mathvariant=¨normal¨»m«/mi»«/mrow»«/mstyle»«/math».
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