# 0.8 Exponential functions and graphs

 Page 1 / 2

## Introduction

In Grade 10, you studied graphs of many different forms. In this chapter, you will learn a little more about the graphs of exponential functions.

## Functions of the form $y=a{b}^{\left(x+p\right)}+q$ For $b>0$

This form of the exponential function is slightly more complex than the form studied in Grade 10.

## Investigation : functions of the form $y=a{b}^{\left(x+p\right)}+q$

1. On the same set of axes, with $-5\le x\le 3$ and $-35\le y\le 35$ , plot the following graphs:
1. $f\left(x\right)=-2·{2}^{\left(x+1\right)}+1$
2. $g\left(x\right)=-1·{2}^{\left(x+1\right)}+1$
3. $h\left(x\right)=0·{2}^{\left(x+1\right)}+1$
4. $j\left(x\right)=1·{2}^{\left(x+1\right)}+1$
5. $k\left(x\right)=2·{2}^{\left(x+1\right)}+1$
Use your results to understand what happens when you change the value of $a$ . You should find that the value of $a$ affects whether the graph curves upwards ( $a>0$ ) or curves downwards ( $a<0$ ). You should also find that a larger value of $a$ (when $a$ is positive) stretches the graph upwards. However, when $a$ is negative, a lower value of $a$ (such as -2 instead of -1) stretches the graph downwards. Finally, note that when $a=0$ the graph is simply a horizontal line. This is why we set $a\ne 0$ in the original definition of these functions.
2. On the same set of axes, with $-3\le x\le 3$ and $-5\le y\le 20$ , plot the following graphs:
1. $f\left(x\right)=1·{2}^{\left(x+1\right)}-2$
2. $g\left(x\right)=1·{2}^{\left(x+1\right)}-1$
3. $h\left(x\right)=1·{2}^{\left(x+1\right)}+0$
4. $j\left(x\right)=1·{2}^{\left(x+1\right)}+1$
5. $k\left(x\right)=1·{2}^{\left(x+1\right)}+2$
Use your results to understand what happens when you change the value of $q$ . You should find that when $q$ is increased, the whole graph is translated (moved) upwards. When $q$ is decreased (poosibly even made negative), the graph is translated downwards.
3. On the same set of axes, with $-5\le x\le 3$ and $-35\le y\le 35$ , plot the following graphs:
1. $f\left(x\right)=-2·{2}^{\left(x+1\right)}+1$
2. $g\left(x\right)=-1·{2}^{\left(x+1\right)}+1$
3. $h\left(x\right)=0·{2}^{\left(x+1\right)}+1$
4. $j\left(x\right)=1·{2}^{\left(x+1\right)}+1$
5. $k\left(x\right)=2·{2}^{\left(x+1\right)}+1$
Use your results to understand what happens when you change the value of $a$ . You should find that the value of $a$ affects whether the graph curves upwards ( $a>0$ ) or curves downwards ( $a<0$ ). You should also find that a larger value of $a$ (when $a$ is positive) stretches the graph upwards. However, when $a$ is negative, a lower value of $a$ (such as -2 instead of -1) stretches the graph downwards. Finally, note that when $a=0$ the graph is simply a horizontal line. This is why we set $a\ne 0$ in the original definition of these functions.
4. Following the general method of the above activities, choose your own values of $a$ and $q$ to plot 5 graphs of $y=a{b}^{\left(x+p\right)}+q$ on the same set of axes (choose your own limits for $x$ and $y$ carefully). Make sure that you use the same values of $a$ , $b$ and $q$ for each graph, and different values of $p$ . Use your results to understand the effect of changing the value of $p$ .

These different properties are summarised in [link] .

 $p<0$ $p>0$ $a>0$ $a<0$ $a>0$ $a<0$ $q>0$ $q<0$

## Domain and range

For $y=a{b}^{\left(x+p\right)}+q$ , the function is defined for all real values of $x$ . Therefore, the domain is $\left\{x:x\in \mathbb{R}\right\}$ .

The range of $y=a{b}^{\left(x+p\right)}+q$ is dependent on the sign of $a$ .

If $a>0$ then:

$\begin{array}{ccc}\hfill {b}^{\left(x+p\right)}& >& 0\hfill \\ \hfill a·{b}^{\left(x+p\right)}& >& 0\hfill \\ \hfill a·{b}^{\left(x+p\right)}+q& >& q\hfill \\ \hfill f\left(x\right)& >& q\hfill \end{array}$

Therefore, if $a>0$ , then the range is $\left\{f\left(x\right):f\left(x\right)\in \left[q,\infty \right)\right\}$ . In other words $f\left(x\right)$ can be any real number greater than $q$ .

If $a<0$ then:

$\begin{array}{ccc}\hfill {b}^{\left(x+p\right)}& >& 0\hfill \\ \hfill a·{b}^{\left(x+p\right)}& <& 0\hfill \\ \hfill a·{b}^{\left(x+p\right)}+q& <& q\hfill \\ \hfill f\left(x\right)& <& q\hfill \end{array}$

how can chip be made from sand
are nano particles real
yeah
Joseph
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
no can't
Lohitha
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
has a lot of application modern world
Kamaluddeen
yes
narayan
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
Other chapter Q/A we can ask