# 1.4 Exponential functions  (Page 2/2)

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## Exponential functions and graphs

1. Draw the graphs of $y={2}^{x}$ and $y={\left(\frac{1}{2}\right)}^{x}$ on the same set of axes.
1. Is the $x$ -axis and asymptote or and axis of symmetry to both graphs ? Explain your answer.
2. Which graph is represented by the equation $y={2}^{-x}$ ? Explain your answer.
3. Solve the equation ${2}^{x}={\left(\frac{1}{2}\right)}^{x}$ graphically and check that your answer is correct by using substitution.
4. Predict how the graph $y=2.{2}^{x}$ will compare to $y={2}^{x}$ and then draw the graph of $y=2.{2}^{x}$ on the same set of axes.
2. The curve of the exponential function $f$ in the accompanying diagram cuts the y-axis at the point A(0; 1) and B(2; 4) is on $f$ .
1. Determine the equation of the function $f$ .
2. Determine the equation of $h$ , the function of which the curve is the reflection of the curve of $f$ in the $x$ -axis.
3. Determine the range of $h$ .

## Summary

• You should know the following charecteristics of functions:
• The given or chosen x-value is known as the independent variable, because its value can be chosen freely. The calculated y-value is known as the dependent variable, because its value depends on the chosen x-value.
• The domain of a relation is the set of all the x values for which there exists at least one y value according to that relation. The range is the set of all the y values, which can be obtained using at least one x value.
• The intercept is the point at which a graph intersects an axis. The x-intercepts are the points at which the graph cuts the x-axis and the y-intercepts are the points at which the graph cuts the y-axis.
• Only for graphs of functions whose highest power is more than 1. There are two types of turning points: a minimal turning point and a maximal turning point. A minimal turning point is a point on the graph where the graph stops decreasing in value and starts increasing in value and a maximal turning point is a point on the graph where the graph stops increasing in value and starts decreasing.
• An asymptote is a straight or curved line, which the graph of a function will approach, but never touch.
• A line about which the graph is symmetric
• The interval on which a graph increases or decreases
• A graph is said to be continuous if there are no breaks in the graph.
• Set notation A set of certain x values has the following form: {x : conditions, more conditions}
• Interval notation Here we write an interval in the form ’lower bracket, lower number, comma, upper number, upper bracket’
• You should know the following functions and their properties:
• Functions of the form $y=ax+q$ . These are straight lines.
• Functions of the Form $y=a{x}^{2}+q$ These are known as parabolic functions or parabolas.
• Functions of the Form $y=\frac{a}{x}+q$ . These are known as hyperbolic functions.
• Functions of the Form $y=a{b}^{\left(x\right)}+q$ . These are known as exponential functions.

## End of chapter exercises

1. Sketch the following straight lines:
1. $y=2x+4$
2. $y-x=0$
3. $y=-\frac{1}{2}x+2$
2. Sketch the following functions:
1. $y={x}^{2}+3$
2. $y=\frac{1}{2}{x}^{2}+4$
3. $y=2{x}^{2}-4$
3. Sketch the following functions and identify the asymptotes:
1. $y={3}^{x}+2$
2. $y=-4.{2}^{x}+1$
3. $y=2.{3}^{x}-2$
4. Sketch the following functions and identify the asymptotes:
1. $y=\frac{3}{x}+4$
2. $y=\frac{1}{x}$
3. $y=\frac{2}{x}-2$
5. Determine whether the following statements are true or false. If the statement is false, give reasons why:
1. The given or chosen y-value is known as the independent variable.
2. An intercept is the point at which a graph intersects itself.
3. There are two types of turning points – minimal and maximal.
4. A graph is said to be congruent if there are no breaks in the graph.
5. Functions of the form $y=ax+q$ are straight lines.
6. Functions of the form $y=\frac{a}{x}+q$ are exponential functions.
7. An asymptote is a straight or curved line which a graph will intersect once.
8. Given a function of the form $y=ax+q$ , to find the y-intersect put $x=0$ and solve for $y$ .
9. The graph of a straight line always has a turning point.
6. Given the functions $f\left(x\right)=-2{x}^{2}-18$ and $g\left(x\right)=-2x+6$
1. Draw $f$ and $g$ on the same set of axes.
2. Calculate the points of intersection of $f$ and $g$ .
3. Hence use your graphs and the points of intersection to solve for $x$ when:
1. $f\left(x\right)>0$
2. $\frac{f\left(x\right)}{g\left(x\right)}\le 0$
4. Give the equation of the reflection of $f$ in the $x$ -axis.
7. After a ball is dropped, the rebound height of each bounce decreases. The equation $y=5·{\left(0,8\right)}^{x}$ shows the relationship between $x$ , the number of bounces, and $y$ , the height of the bounce, for a certain ball. What is the approximate height of the fifth bounce of this ball to the nearest tenth of a unit ?
8. Mark had 15 coins in five Rand and two Rand pieces. He had 3 more R2-coins than R5-coins. He wrote a system of equations to represent this situation, letting $x$ represent the number of five rand coins and $y$ represent the number of two rand coins. Then he solved the system by graphing.
1. Write down the system of equations.
2. Draw their graphs on the same set of axes.
3. What is the solution?

find the 15th term of the geometric sequince whose first is 18 and last term of 387
I know this work
salma
The given of f(x=x-2. then what is the value of this f(3) 5f(x+1)
hmm well what is the answer
Abhi
how do they get the third part x = (32)5/4
can someone help me with some logarithmic and exponential equations.
20/(×-6^2)
Salomon
okay, so you have 6 raised to the power of 2. what is that part of your answer
I don't understand what the A with approx sign and the boxed x mean
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
oops. ignore that.
so you not have an equal sign anywhere in the original equation?
hmm
Abhi
is it a question of log
Abhi
🤔.
Abhi
I rally confuse this number And equations too I need exactly help
salma
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salma
Commplementary angles
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Sherica
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Sherica
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Tamia
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Uday
hi
salma
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a perfect square v²+2v+_
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algebra 2 Inequalities:If equation 2 = 0 it is an open set?
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
y=10×
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
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Kristine 2*2*2=8
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what's the easiest and fastest way to the synthesize AgNP?
China
Cied
types of nano material
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
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Porter
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Yasmin
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Cesar
I'm interested in nanotube
Uday
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preparation of nanomaterial
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
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Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
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Prasenjit
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Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
how did you get the value of 2000N.What calculations are needed to arrive at it
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