Nelson Functions 11
Nelson Functions 11
1st Edition
Chris Kirkpatrick, Marian Small
ISBN: 9780176332037
Textbook solutions

All Solutions

Page 376: Practice Questions

Exercise 1
Step 1
1 of 3
We must sketch the graph such that the distance between two consecutive peaks is 10, $y_{min}=4$ and $y_{max}=10$

The equation of the axis must be $y=dfrac{4+10}{2}implies y=7$
and the amplitude is $A=dfrac{|10-4|}{2}=3$

Using this information, we can sketch the following.

Step 2
2 of 3
Exercise scan
Result
3 of 3
See graph inside.
Exercise 2
Step 1
1 of 3
a) We can plot the given points and sketch the graph as follows.Exercise scan
Step 2
2 of 3
b) The graph is periodic because it repeats at regular intervals.

c) The period of the function is $8$ s.

d) From the graph $y_{min}=60$ and $y_{max}=100$. Thus, the equation of the axis is $y=dfrac{y_{min}+y_{max}}{2}=dfrac{60+100}{2}implies y=80$

e) The amplitude is $A=dfrac{|y_{max}-y_{min}|}{2}=dfrac{|100-60|}{2}implies A=20$

f) The rate of pressure increase is the slope of the line from $t=1$ to $t=3$ which is $dfrac{100-60}{3-1}=20$ psi/s

g) The rate of pressure decrease is the slope of the line from $t=4$ to $t=8$ which is $dfrac{60-100}{8-4}=-10$ psi/s. The negative indicates that the pressure is decreasing so the magnitude is just $10$ psi/s

h) The container is never empty on the time interval given since the minimum pressure is 60 psi which is above the normal atmospheric pressure (14.7 psi).

Result
3 of 3
a) see graph

b) repeats at regular intervals

c) 8 s

d) $y=80$

e) $A=20$

f) $20$ psi/s

g) $10$ psi/s

h) No

Exercise 3
Step 1
1 of 5
[begin{gathered}
{mathbf{Useful}}{text{ }}{mathbf{Definitions}} hfill \
{text{equation of the axis: }},,y = frac{{{y_{max }} + {y_{min }}}}{2} hfill \
{text{amplitude: }}A = {text{ }}frac{{left| {{y_{max }} – {y_{min }}} right|}}{2} hfill \
{text{period}} = left| {{x_2} – {x_1}} right| hfill \
hfill \
{text{For a sinusoidal function}} hfill \
hfill \
y = Acos left( {kx} right) + B{text{ or }}y = Asin left( {kx} right) + B hfill \
hfill \
{text{amplitude = }}A hfill \
{text{period = }}frac{{{{360}^ circ }}}{k} hfill \
{text{equation of axis:}}{text{ }},,,y = B hfill \
end{gathered} ]Exercise scan
Step 2
2 of 5
a) Given that $g(x)=5cos (2x)+7$, we can see that

period = $dfrac{360^circ}{2}=180^circ$

equation of axis : $y=7$

amplitude : $A=5$

range: ${ g(x) in bold{R};|;2leq g(x)leq 12}$

The graph can be sketched following the given specifications.

Exercise scan

Step 3
3 of 5
b) The graph is a smooth symmetrical curves and is obtained from transformation of a cosine function.

c) $g(125)=5cos(2cdot 125)+7approx 5.2899$

Step 4
4 of 5
d) $g(x) = 12$ within the given interval for $x={0,180,360}$

Exercise scan

Result
5 of 5
a)
period = $180^circ$

equation of axis : $y=7$

amplitude : $A=5$

range: ${ g(x) in bold{R};|;2leq g(x)leq 12}$

b) see explanation inside

c) $g(125)approx 5.2899$

d) $x={0,180,360}$

Exercise 4
Step 1
1 of 3
The coordinates of the new point after a rotation of $theta ^circ$ about the origin (0,0) from the point $(r,0)$ is $(x,y)$ such that $x=rcostheta$ and $y=rsintheta$.

Exercise scan

Step 2
2 of 3
In this case, $r=7$ and $theta=64^circ$, thus,

$x=7cos 64^circapprox 3.0686$

$y=7sin 64^circapprox 6.2916$

Thus, the new point is (3.07,6.29)

Result
3 of 3
(3.07,6.29)
Exercise 5
Step 1
1 of 3
[begin{gathered}
{mathbf{Useful}}{text{ }}{mathbf{Definitions}} hfill \
{text{equation of the axis: }},,y = frac{{{y_{max }} + {y_{min }}}}{2} hfill \
{text{amplitude: }}A = {text{ }}frac{{left| {{y_{max }} – {y_{min }}} right|}}{2} hfill \
{text{period}} = left| {{x_2} – {x_1}} right| hfill \
hfill \
{text{For a sinusoidal function}} hfill \
hfill \
y = Acos left( {kx} right) + B{text{ or }}y = Asin left( {kx} right) + B hfill \
hfill \
{text{amplitude = }}A hfill \
{text{period = }}frac{{{{360}^ circ }}}{k} hfill \
{text{equation of axis:}}{text{ }},,,y = B hfill \
end{gathered} ]Exercise scan
Step 2
2 of 3
$bold{a)}$ The period of both Mark 1 and Mark 2 is $0.25-0=0.25$ s. The period represents the time for the wheel to complete 1 revolution.

$bold{b)}$ The equation of the axis is the midline between the highest and minimum point which we can read from the graph as $y=30$. It represents the vertical distance of the center of the wheel.

$bold{c)}$ The amplitude of Mark 1 is $A=dfrac{60-0}{2}=30$ cm while that of Mark 2 is $dfrac{50-10}{2}=20$ cm. It represents the distance of the mark from the center of the wheel.

$bold{d)}$ The range is from the minimum point to maximum point which can be written as

For mark 1: ${ h(t) in bold{R};|;0leq h(t) leq 60}$

For mark 2: ${ h(t) in bold{R};|;10leq h(t) leq 50}$

$bold{e)}$ The speed of each mark is the circumference $(2pi times A)$ divided by the period.

mark 1: $v=dfrac{2picdot 30}{0.25}=753.98$ cm/s

mark 2: $v=dfrac{2picdot 20}{0.25}=502.65$ cm/s

$bold{f)}$ A third mark closer to the center is expected to have lower amplitude than Mark 2 but the same period and axis as Mark 1 and Mark 2.

Result
3 of 3
a) 0.25 s for both

b) $y=30$ cm

c) mark 1: A = 30 cm ; mark 2: A = 20 cm

d) mark 1: ${ h(t) in bold{R};|;0leq h(t) leq 60}$, mark 2: ${ h(t) in bold{R};|;10leq h(t) leq 50}$

e) mark 1: $753.98$ cm/s , mark 2: $502.65$ cm/s

f) lower amplitude but the same axis and period

Exercise 6
Step 1
1 of 3
[begin{gathered}
{mathbf{Useful}}{text{ }}{mathbf{Definitions}} hfill \
{text{equation of the axis: }},,y = frac{{{y_{max }} + {y_{min }}}}{2} hfill \
{text{amplitude: }}A = {text{ }}frac{{left| {{y_{max }} – {y_{min }}} right|}}{2} hfill \
{text{period}} = left| {{x_2} – {x_1}} right| hfill \
hfill \
{text{For a sinusoidal function}} hfill \
hfill \
y = Acos left( {kx} right) + B{text{ or }}y = Asin left( {kx} right) + B hfill \
hfill \
{text{amplitude = }}A hfill \
{text{period = }}frac{{{{360}^ circ }}}{k} hfill \
{text{equation of axis:}}{text{ }},,,y = B hfill \
end{gathered} ]Exercise scan
Step 2
2 of 3
$bold{a)}$ Given that $P(d)=28sin left(dfrac{360}{365}d-81right)^circ$. The graph can be sketched as follows.

$bold{b)}$ The period of the function is $T=dfrac{360^circ}{(360/365)}=365$

It represents the number of days in a year in which the cycle goes through.

$bold{c)}$ The equation of the axis (midline between maximum and minimum point) is $y=0$. It represents the position of $0^circ$ with respect to due west.

$bold{d)}$ From the given function, the amplitude is $A=28$

$bold{e)}$ The range of the function is the set of $P(d)$ values from minimum to maximum point.

${ P(d) in bold{R};|;-28leq P(d) leq 28}$

$bold{f)}$ February 15 corresponds to the 46th day of the year, thus we shall evaluate $P(46)$

$$
P(46)=28cdot sinleft(dfrac{360}{365}(46)-81right)^circ=-16.3^circ
$$

Exercise scan

Result
3 of 3
a) see graph

b) 365

c) $y=0$

d) $A=28$

e) ${ P(d) in bold{R};|;-28leq P(d) leq 28}$

f) $-16.3^circ$

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