# 1.4 Homework: functions in the real world

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This module provides practice problems designed to mimic real life applications of functions.

Laura is selling doughnuts for 35¢ each. Each customer fills a box with however many doughnuts he wants, and then brings the box to Laura to pay for them. Let n represent the number of doughnuts in a box, and let $c$ represent the cost of the box (in cents).

• If the box has 3 doughnuts, how much does the box cost?
• If $c=\text{245}$ , how much does the box cost? How many doughnuts does it have?
• If a box has n doughnuts, how much does it cost?
• Write a function $c\left(n\right)$ that gives the cost of a box , as a function of the number of doughnuts in the box.

Worth is doing a scientific study of graffiti in the downstairs boy’s room. On the first day of school, there is no graffiti. On the second day, there are two drawings. On the third day, there are four drawings. He forgets to check on the fourth day, but on the fifth day, there are eight drawings. Let d represent the day, and g represent the number of graffiti marks that day.

• Fill in the following table, showing Worth’s four data points.  d (day) g (number of graffiti marks)
• If this pattern keeps up, how many graffiti marks will there be on day 10?
• If this pattern keeps up, on what day will there be 40 graffiti marks?
• Write a function $g\left(d\right)$ ) that gives the number of graffiti marks as a function of the day .

Each of the following is a set of points. Next to each one, write “yes” if that set of points could have been generated by a function, and “no” if it could not have been generated by a function. (You do not have to figure out what the function is. But you may want to try for fun—I didn’t just make up numbers randomly…)

• $\left(1,-1\right)\left(3,-3\right)\left(-1,-1\right)\left(-3,-3\right)$ ________
• $\left(1,\pi \right)\left(3,\pi \right)\left(9,\pi \right)\left(\pi ,\pi \right)$ ________
• $\left(1,1\right)\left(-1,1\right)\left(2,4\right)\left(-2,4\right)\left(3,9\right)\left(-3,9\right)$ ________
• $\left(1,1\right)\left(1,-1\right)\left(4,2\right)\left(4,-2\right)\left(9,3\right)\left(9,-3\right)$ ________
• $\left(1,1\right)\left(2,3\right)\left(3,6\right)\left(4,\text{10}\right)$ ________

$f\left(x\right)={x}^{2}+2x+1$

• $f\left(2\right)=$
• $f\left(-1\right)=$
• $f\left(\frac{3}{2}\right)=$
• $f\left(y\right)=$
• $f\left(\text{spaghetti}\right)=$
• $f\left(\sqrt{x}\right)$
• $f\left(f\left(x\right)\right)$

Make up a function that has something to do with movies .

• Think of a scenario where there are two numbers, one of which depends on the other. Describe the scenario, clearly identifying the independent variable and the dependent variable .
• Write the function that shows how the dependent variable depends on the independent variable.
• Now, plug in an example number to show how it works.

where we get a research paper on Nano chemistry....?
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
what about nanotechnology for water purification
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
how did you get the value of 2000N.What calculations are needed to arrive at it
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