Answer:
1/25=3/30
1250=
2501
2389
5552
A hospital director is told that 54% of the emergency room visitors are insured. The director wants to test the claim that the percentage of insured patients is under the expected percentage. A sample of 120 patients found that 60 were insured. Find the value of the test statistic. Round your answer to two decimal places.
Answer:
Z -0.879173965
Step-by-step explanation:
Z -0.879173965
ρ 0.5
π 0.54
n 120
The value of the test statistic is the z-score z = -0.88
What is a z-score?The relationship between a value and the mean of a set of values is expressed numerically by a Z-score. The Z-score is computed using the standard deviations from the mean. A Z-score of zero indicates that the data point's score and the mean score are identical.
The Z-score is calculated using the formula:
z = (x - μ)/σ
where z: standard score
x: observed value
μ: mean of the sample
σ: standard deviation of the sample
Given data ,
Let the test statistic value be represented as z
Now , the probability of emergency room visitors are insured is q = 0.54
The total number of patients n = 120
The number of patients that were insured = 60
So , the percentage of people that were insured p = 60/120 = 0.5
Now , test statistic value z = ( p - q ) / [ √ ( q ( 1 - q )/n² ]
The value of z score is
z = [ 0.5 - 0.54 ] / √ 0.54 ( 1 - 0.54 ) / 120²
On simplifying the equation , we get
The value of z score is z = -0.88
Hence , the test statistic is z = -0.88
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Tìm thể tích của khối bao bởi mặt z=5+(x−4)^2+2y và mặt x=3,y=4 và mặt phẳng tọa độ.
Step-by-step explanation:
ccxiddidificifificici i i ivi i i i i i i i iivvii iix9difi
For a sample variance of n = 36 that has a sample variance of 1,296, what is the estimated error for the sample?
Answer:
6
Step-by-step explanation:
Given :
Sample size, n = 36
Sample variance, s² = 1296
The estimated standard error can be obtained using the relation :
Standard Error, S. E = standard deviation / √n
Standard deviation, s = √1296 = 36
S.E = 36/√36
S.E = 36/6
S.E = 6
Hence, estimated standard error = 6
The graph below shows two polynomial functions, f(x) and g(x): Graph of f of x equals x squared minus 2 x plus 1. Graph of g of x equals x cubed plus 1 Which of the following statements is true about the graph above? (4 points) g(x) is an even degree polynomial with a positive leading coefficient. g(x) is an odd degree polynomial with a negative leading coefficient. f(x) is an even degree polynomial with a positive leading coefficient. f(x) is an odd degree polynomial with a negative leading coefficient.
9514 1404 393
Answer:
(c) f(x) is an even degree polynomial with a positive leading coefficient.
Step-by-step explanation:
The leading terms of the two functions are ...
f(x): x² (even degree, positive coefficient: 1)
g(x): x³ (odd degree, positive coefficient: 1)
Then it is true that ...
f(x) is an even degree polynomial with a positive leading coefficient
An electronic switching device occasionally malfunctions, but the device is considered satisfactory if it makes, on average, no more than 0.20 error per hour. A particular 5-hour period is chosen for testing the device. If no more than 1 error occurs during the time period, the device will be considered satisfactory.
(a) What is the probability that a satisfactory device will be considered unsatisfactory on the basis of the test? Assume a Poisson process.
(b) What is the probability that a device will be accepted as satisfactory when, in fact, the mean number of errors is 0.25? Again, assume a Poisson process.
Solution :
It is given that the device works satisfactorily if it makes an average of no more than [tex]0.2[/tex] errors per hour.
The number of errors thus follows the Poisson distribution.
It is given that in [tex]5[/tex] hours test period, the number of the errors follows is
= [tex]0.2 \times 5[/tex]
= 1 error
Let X = the number of the errors in the [tex]5[/tex] hours
[tex]$X \sim \text{Poisson } (\lambda = 0.2 \times 5 =1)$[/tex]
Now that we want to find the [tex]\text{probability}[/tex] that a [tex]\text{satisfactory device}[/tex] will be misdiagnosed as "[tex]\text{unsatisfactory}[/tex]" on the basis of this test. We know that device will be unsatisfactory if it makes more than [tex]1[/tex] error in the test. So we will determine probability that X is greater than [tex]1[/tex] to get required answer.
So the required probability is :
[tex]P(X>1)[/tex]
[tex]$=1-P(X \leq 1)$[/tex]
[tex]$=1-[P(X=0)+P(X=1)]$[/tex]
[tex]$=1- \left( \frac{e^{-1} 1^0}{0!} + \frac{e^{-1} 1^0}{1!} \right) $[/tex]
[tex]$=1-(2 \times e^{-1})$[/tex]
[tex]$=1-( 2 \times 0.367879)$[/tex]
[tex]$=1-0.735759$[/tex]
[tex]=0.264241[/tex]
So the [tex]\text{probability}[/tex] that the [tex]\text{satisfactory device}[/tex] will be misdiagnosed as "[tex]\text{unsatisfactory}[/tex]" on the basis of the test whose result is 0.264241
Please help!! Can’t figure this out for the life of me.
Select the correct answer from each drop-down menu.
If _______, then AABC and ADEF are congruent by the ASA criterion.
If _______, then AABC and ADEF are congruent by the SAS criterion.
AABC and ADEF are congruent if ______
Answer:
Angle b is congruent to angle E
CA=FD
Step-by-step explanation:
If _______, then triangle ABC and triangle DEF are congruent by the ASA criterion. ASA is angle side angle . We know angle C= angle F and side CB = side FE We need to know angle B = angle E
If _______, then triangle ABC and triangle DEF are congruent by the SAS criterion. SAS is side angle side, we know side CB = side FE and then angle C= angle F then we need side CA = side FD
If ∠ABC = ∠DEF, then ΔABC and ΔDEF are congruent by the ASA criterion.
If AC = DF, then ΔABC and ΔDEF are congruent by the SAS criterion.
What are congruent figures?Two figures are said to be congruent of they have the same shape and all the corresponding sides and angles are congruent.
The HL (hypotenuse leg) congruence theorem states that if the hypotenuse and one leg of a triangle is congruent to another triangle, then both triangles are congruent.
In triangle ABC and DEF;
BC = EF and ∠ACB ≅ ∠DFE
Hence:
If ∠ABC = ∠DEF, then ΔABC and ΔDEF are congruent by the ASA criterion.
If AC = DF, then ΔABC and ΔDEF are congruent by the SAS criterion.
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PLEASEEEE HELP
In the diagram, AABC-ADEC What is the value of x?
Similar triangles are proportional, meaning one will be a factor larger or smaller than the other. This factor will be the same for all of the sides. So, we can say that one corresponding pair of sides is equal to another corresponding pair of sides.
BA / ED = AC / CD
42 / 6 = (64 - x) / (x)
6(64 - x) = 42(x)
384 - 6x = 42x
384 = 48x
x = 8
Hope this helps!
Fill in the blank with a number to make the expression a perfect square.
u^2- 18u +
Answer:
u^2- 18u +81 = (u-9)^2
Step-by-step explanation:
u^2- 18u +
Take the u coefficient
-18
Divide by 2
-18/2 = -9
Square it
(-9)^2 = 81
u^2- 18u +81 = (u-9)^2
Answer:
The blank should contain 81
Step-by-step explanation:
E = u^2 - 18u + (-18/2)^2
E = (u^2 - 18u + 9^2)
E = (u - 9)^2
To be perfectly correct what you have there is a perfect square, but you need to subtract out (9/2)^2 to make it a valid statement.
E = (u - 9)^2 - 81
A lawyer commutes daily from his suburban home to his midtown office. The average time for a one-way trip is 24 minutes, with a standard deviation of 3.8 minutes. Assume the distribution of trip times to be normally distributed.
(a) What is the probability that a trip will take at least ½ hour?
(b) If the office opens at 9:00 A.M. and he leaves his house at 8:45 A.M. daily, what percentage of the time is he late for work?
(c) If he leaves the house at 8:35 A.M. and coffee is served at the office from 8:50 A.M. until 9:00 A.M., what is the probability that he misses coffee?
(d) Find the length of time above which we find the slowest 10% of trips.
(e) Find the probability that 2 of the next 3 trips will take at least one half
1/2 hour.
Answer:
Step-by-step explanation:
a) Probability-Above 30 min = 5.72% = .0572
b) Probability-Above 15 min = 99.11% = .9911
c) *Probability-Between 1 - 59.49% = .4051
d) 19.136 minutes z = -1.28
a) The probability that trip will take at least 1/2 hour will be 0.0606.
b) The percentage of time the lawyer is late for work will be 99.18%.
c) The probability that lawyer misses coffee will be 0.3659.
d) The length of time above which we find the slowest 10% of trips will be 0.5438.
e) The probability that exactly 2 out of 3 trips will take at least one half
1/2 hour is 0.0103.
What do you mean by normal distribution ?
A probability distribution known as a "normal distribution" shows that data are more likely to occur when they are close to the mean than when they are far from the mean.
Let assume the time taken for a one way trip be x .
x ⇒ N( μ , σ ²)
x ⇒ N( 24 , 3.8 ²)
a)
The probability that trip will take at least 1/2 hour or 30 minutes will be :
P ( x ≥ 30)
= P [ (x - μ) / σ ≥ (30 - μ) / σ ]
We know that , (x - μ) / σ = z.
= P [ z ≥ (30 - 24) / 3.8)]
= P [ z ≥ 1.578 ]
= 1 - P [ z ≤ 1.578 ]
Now , using the standard normal table :
P ( x ≥ 30)
= 1 - 0.9394
= 0.0606
b)
The percentage of the time the lawyer is late for work will be :
P ( x ≥ 15)
= P [ z ≥ -2.368 ]
= P [ z ≤ 2.368]
= 0.9918
or
99.18%
c)
The probability that lawyer misses coffee :
P ( 15 < x < 25 ) = P ( x < 25 ) - P ( x < 15)
= P [ z < 0.263] - P ( z < -2.368)
or
= 0.3659
d)
The length of time above which we find the slowest 10% of trips :
P( x ≥ X ) ≤ 0.10
= 0.5438
e)
Let's assume that y represents the number of trips that takes at least half hour.
y ⇒ B ( n , p)
y ⇒ B ( 3 , 0.0606)
So , the probability that exactly 2 out of 3 trips will take at least one half
1/2 hour is :
P ( Y = 2 )
= 3C2 × (0.0606)² × ( 1 - 0.0606)
= 0.0103
Therefore , the answers are :
a) The probability that trip will take at least 1/2 hour will be 0.0606.
b) The percentage of time the lawyer is late for work will be 99.18%.
c) The probability that lawyer misses coffee will be 0.3659.
d) The length of time above which we find the slowest 10% of trips will be 0.5438.
e) The probability that exactly 2 out of 3 trips will take at least one half
1/2 hour is 0.0103.
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evaluate (-1)^6-4^0+(3/7)^0
Answer:
The answer is 1
.............
please mark this answer as brainlist
what’s the value of x? and what’s the measure of angel JHK?
Answer:
x = 14
JHK = 21
Step-by-step explanation:
The angles are vertical angles and vertical angles are equal
3x-21 = x+7
Subtract x from each side
3x-x -21 = x+7-x
2x-21 = 7
Add 21 to each side
2x-21+21 = 7+21
2x = 28
Divide by 2
2x/2 =28/2
x = 14
JHK = 3x-21 = 3(14) -21 = 42-21 = 21
Answer:
Because ∠GHI and ∠JHK are vertical angles, they're congruent. Therefore, set their angle measures equal to each other & solve for x.
[tex]x+7=3x-21\\x-3x=-7-21\\-2x=-28\\x=\frac{-28}{-2} =14\°[/tex]
Substitute in the value of x to find ∠JHK:
[tex]3x-21=3(14)-21=42-21=21\°[/tex]
Please help!! Given the recursive formula shown, what are the first 4 terms of the sequence?
Answer:
C
Step-by-step explanation:
the fibrin definition tells us that the first term of the sequence a1 = 6
so, B is out.
and for every following term we always add 7 to every previous term to create the next one.
so, when I add 7 to 6, what is my second term in the sequence ? 7+6 = 13
not 42, not -7
therefore, only C is correct.
and 13+7 = 20
and 20+7 = 27
it all fits
the mean salary if of 5 employees is $35900. the median is $37000. the mode is $382000. If the median payed employee gets a $3100 raise, then…
New median:
New mode:
Answer:
Step-by-step explanation:
New median:40100
New mode:385100
An exterior angle of a regular polygon cannot have the measure of
Select one:
a. 120
b. 40
c. 50
d. 90
e. 30
Cual es el capital que prestado al 10% bimestral durante 6 meses y 10 días produce un interés de 1140
Respuesta:
3650
Explicación paso a paso:
Dado que :
Principal, P = capital prestado
Tasa anual, r = 10% * 6 = 60%
Interés = 1140
Periodo = 6 meses y 10 días = (6 * 30) +10 = 190 días
Conversión a años:
Periodo = 190/365
Usando la relación:
Interés = principal * tasa * tiempo
1140 = P * 60% * (190/365)
1140 = 0.3123287P
P = 1140 / 0,3123287
P = 3650
the length of a rectangle is 4 meters longer than the width. if the area is 22 square meters , find the rectangle dimension
Let breadth be x
Length=x+4We know
[tex]\boxed{\sf Area_{(Rectangle)}=Length\times Breadth}[/tex]
[tex]\\ \sf\longmapsto x(x+4)=22[/tex]
[tex]\\ \sf\longmapsto x^2+4x=22[/tex]
[tex]\\ \sf\longmapsto x^2+4x-22=0[/tex]
By solving[tex]\\ \sf\longmapsto x=-2\pm\sqrt{26}[/tex]
It doesnot have any real roots
A person earns $23,600 one year and gets a 5% raise in salary. What is the new salary?
Answer:
24780
Step-by-step explanation:
might not be right but 24780 because 23600*5% is 1180 and add that to the original 23600 to get 24780
5% more is 105% in total, including the the 100% we start with, so:
23,600 * 1.05 = 24780
Can someone let me know if this is right? Show work.
Answer:
I'd be estimatining the answer between 29-31.
Draw a line of best fit. It will be easier to make the estimation.
Describe domain and range of the graph.
please help i need this by tonight
Answer:
The measure of ∠1 and ∠2 is 105° and 75° respectively
Step-by-step explanation:
In the given figure, line a is parallel to line b.
We need to find the measure of angles 1 and 2.
∠2 = 75° (because they form corresponding angles)
We know that, interior angles add up to 180. So,
∠1 +75 = 180
∠1 = 180-75
∠1 = 105°
So, the measure of ∠1 and ∠2 is 105° and 75° respectively.
d(1)=2
d(n)=d(n−1)⋅(−2)^n
What is the third term in the sequence?
Answer:
- 16
Step-by-step explanation:
The way this is given, you have to find the second term before you can fine the third.
a2 = d(n - 1) * (-2)^2
a2 = 2 * (-2)^2
a2 = 2 * 4
a2 = 8
a3 = d(3 - 1) * (-2)^3
a3 = 2 * (-2)^3
a3 = 2 * - 8
a3 = - 16
please help me with geometry
Answer:
A. If the side lengths are the same, then a triangle is not scalene.
Step-by-step explanation:
A triangle can be defined as a two-dimensional shape that comprises three (3) sides, three (3) vertices and three (3) angles.
Simply stated, any polygon with three (3) lengths of sides is a triangle.
In Geometry, a triangle is considered to be the most important shape.
Generally, there are three (3) main types of triangle based on the length of their sides and these include;
I. Equilateral triangle: it has all of its three (3) sides and interior angles equal.
II. Isosceles triangle: it has two (2) of its sides equal in length and two (2) equal angles.
III. Scalene triangle: it has all of its three (3) sides and interior angles different in length and size respectively.
It is estimated that 75% of all young adults between the ages of 18-35 do not have a landline in their homes and only use a cell phone at home.
(a) On average, how many young adults do not own a landline in a random sample of 100?
(b) What is the standard deviation of probability of young adults who do not own a landline in a simple random sample of 100?
(c) What is the proportion of young adults who do not own a landline?
(d) What is the probability that no one in a simple random sample of 100 young adults owns a landline?
(e) What is the probability that everyone in a simple random sample of 100 young adults owns a landline?
(f) What is the distribution of the number of young adults in a sample of 100 who do not own a landline?
(g) What is the probability that exactly half the young adults in a simple random sample of 100 do not own a landline?
Answer:
a) 75
b) 4.33
c) 0.75
d) [tex]3.2 \times 10^{-13}[/tex] probability that no one in a simple random sample of 100 young adults owns a landline
e) [tex]6.2 \times 10^{-61}[/tex] probability that everyone in a simple random sample of 100 young adults owns a landline.
f) Binomial, with [tex]n = 100, p = 0.75[/tex]
g) [tex]4.5 \times 10^{-8}[/tex] probability that exactly half the young adults in a simple random sample of 100 do not own a landline.
Step-by-step explanation:
For each young adult, there are only two possible outcomes. Either they do not own a landline, or they do. The probability of an young adult not having a landline is independent of any other adult, which means that the binomial probability distribution is used to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.
[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]
And p is the probability of X happening.
The expected value of the binomial distribution is:
[tex]E(X) = np[/tex]
The standard deviation of the binomial distribution is:
[tex]\sqrt{V(X)} = \sqrt{np(1-p)}[/tex]
75% of all young adults between the ages of 18-35 do not have a landline in their homes and only use a cell phone at home.
This means that [tex]p = 0.75[/tex]
(a) On average, how many young adults do not own a landline in a random sample of 100?
Sample of 100, so [tex]n = 100[/tex]
[tex]E(X) = np = 100(0.75) = 75[/tex]
(b) What is the standard deviation of probability of young adults who do not own a landline in a simple random sample of 100?
[tex]\sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{100(0.75)(0.25)} = 4.33[/tex]
(c) What is the proportion of young adults who do not own a landline?
The estimation, of 75% = 0.75.
(d) What is the probability that no one in a simple random sample of 100 young adults owns a landline?
This is P(X = 100), that is, all do not own. So
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 100) = C_{100,100}.(0.75)^{100}.(0.25)^{0} = 3.2 \times 10^{-13}[/tex]
[tex]3.2 \times 10^{-13}[/tex] probability that no one in a simple random sample of 100 young adults owns a landline.
(e) What is the probability that everyone in a simple random sample of 100 young adults owns a landline?
This is P(X = 0), that is, all own. So
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 0) = C_{100,0}.(0.75)^{0}.(0.25)^{100} = 6.2 \times 10^{-61}[/tex]
[tex]6.2 \times 10^{-61}[/tex] probability that everyone in a simple random sample of 100 young adults owns a landline.
(f) What is the distribution of the number of young adults in a sample of 100 who do not own a landline?
Binomial, with [tex]n = 100, p = 0.75[/tex]
(g) What is the probability that exactly half the young adults in a simple random sample of 100 do not own a landline?
This is P(X = 50). So
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 50) = C_{100,50}.(0.75)^{50}.(0.25)^{50} = 4.5 \times 10^{-8}[/tex]
[tex]4.5 \times 10^{-8}[/tex] probability that exactly half the young adults in a simple random sample of 100 do not own a landline.
Give the domain and range of G={(6.0),(-9,-3),(1,-3)}
Answer:
Step-by-step explanation:
D={ 6 , -9 , 1 }
R={ 0 ,-3 }
use de moivre's theorem to write
[2(cos 12 degrees + i sin 12 degrees)]^5
in standard form
DeMoivre's theorem says
(2 (cos(12°) + i sin(12°)))⁵ = 2⁵ (cos(5×12°) + i sin(5×12°))
… = 32 (cos(60°) + i sin(60°))
… = 32 (1/2 + √3/2 i )
… = 16 + 16√3 i
Please help with Question 2b
Answer:
MUST BE IN HLA, NOT FROM C TO ASSEMBLY.
PROGRAM 6: Same
Write an HLA Assembly language program that implements a function which correctly identifies when all four parameters are the same and returns a boolean value in AL (1 when all four values are equal; 0 otherwise). This function should have the following signature:
procedure theSam
Below is the graph of a polynomial function with real coefficients
(a) The function f is increasing over which intervals? Choose all that apply.
D(-0, -8)
O (-5,-2) O (-8, -2) O (-2,
2) (2,5)
O (5, 0 )
?
(b) The functionfhas local maxima at which x-values? If there is more than one value,
separate them with commas.
(c) What is the sign of the leading coefficient of f?
Select One
(d) Which of the following is a possibility for the degree of f? Choose all that apply.
4
5
6
Please help if you can thank you
9514 1404 393
Answer:
(a) (-∞, -8), (-5, -2), (2, 5)
(b) -8, -2, 5
(c) negative
(d) 6
Step-by-step explanation:
(a) The function is increasing on intervals where the graph slopes upward left-to-right. Those are (-∞, -8), (-5, -2), and (2, 5).
__
(b) The local maxima are at the right end of each interval on which the function is increasing: -8, -2, 5.
__
(c) The function opens downward (∩), so has a negative leading coefficient.
__
(d) There are three local maxima and two local minima (left end of an increasing interval), so a total o 5 turning points. The degree of the polynomial is at least one more than this: 6.
A smartphone consumes 4 watts of power when charging. Your power company charges 12 cents per kilowatt hour (kWh). If you leave your smartphone plugged in to the wall outlet for 24 hours, how many cents does this cost
Answer:
[tex]C=1.15cents[/tex]
Step-by-step explanation:
Generally the equation for is mathematically given by
Charge Power P=4watts
Rate r=12cents/hour
Time consumed T=24
Generally
Power consumed by smartphone in 24 hours
[tex]P_t=P*T\\\\P_t=24*4[/tex]
[tex]P_t=0.096kwh[/tex]
Therefore the Cost will be
[tex]C=12*0.096kwh[/tex]
[tex]C=1.15cents[/tex]
give an example of a piecewise function
Answer:
f(x) = 6 when -5 < x ≤ -1
Step-by-step explanation:
help with 4b thank you.
First let's compute dx/dt
[tex]x = t - \frac{1}{t}\\\\x = t - t^{-1}\\\\\frac{dx}{dt} = \frac{d}{dt}\left(t - t^{-1}\right)\\\\\frac{dx}{dt} = 1-(-1)t^{-2}\\\\\frac{dx}{dt} = 1+\frac{1}{t^{2}}\\\\\frac{dx}{dt} = \frac{t^2}{t^{2}}+\frac{1}{t^{2}}\\\\\frac{dx}{dt} = \frac{t^2+1}{t^{2}}\\\\[/tex]
Now compute dy/dt
[tex]y = 2t + \frac{1}{t}\\\\y = 2t + t^{-1}\\\\\frac{dy}{dt} = \frac{d}{dt}\left(2t + t^{-1}\right)\\\\\frac{dy}{dt} = 2 - t^{-2}\\\\\frac{dy}{dt} = 2 - \frac{1}{t^2}\\\\\frac{dy}{dt} = \frac{2t^2}{t^2}-\frac{1}{t^2}\\\\\frac{dy}{dt} = \frac{2t^2-1}{t^2}\\\\[/tex]
From here, apply the chain rule to say
[tex]\frac{dy}{dx} = \frac{dy*dt}{dx*dt}\\\\\frac{dy}{dx} = \frac{dy}{dt} \times \frac{dt}{dx}\\\\\frac{dy}{dx} = \frac{dy}{dt} \div \frac{dx}{dt}\\\\\frac{dy}{dx} = \frac{2t^2-1}{t^2} \div \frac{t^2+1}{t^{2}}\\\\\frac{dy}{dx} = \frac{2t^2-1}{t^2} \times \frac{t^{2}}{t^2+1}\\\\\frac{dy}{dx} = \frac{2t^2-1}{t^2+1}\\\\[/tex]
We could use polynomial long division, or we could add 2 and subtract 2 from the numerator and do a bit of algebra like so
[tex]\frac{dy}{dx} = \frac{2t^2-1}{t^2+1}\\\\\frac{dy}{dx} = \frac{2t^2-1+2-2}{t^2+1}\\\\\frac{dy}{dx} = \frac{(2t^2+2)-1-2}{t^2+1}\\\\\frac{dy}{dx} = \frac{2(t^2+1)-3}{t^2+1}\\\\\frac{dy}{dx} = \frac{2(t^2+1)}{t^2+1}-\frac{3}{t^2+1}\\\\\frac{dy}{dx} = 2-\frac{3}{t^2+1}\\\\[/tex]
This concludes the first part of 4b
=======================================================
Now onto the second part.
Since t is nonzero, this means either t > 0 or t < 0.
If t > 0, then,
[tex]t > 0\\\\t^2 > 0\\\\t^2+1 > 1\\\\\frac{1}{t^2+1} < 1 \ \text{ ... inequality sign flip}\\\\\frac{3}{t^2+1} < 3\\\\-\frac{3}{t^2+1} > -3 \ \text{ ... inequality sign flip}\\\\-\frac{3}{t^2+1}+2 > -3 + 2\\\\2-\frac{3}{t^2+1} > -1\\\\-1 < 2-\frac{3}{t^2+1}\\\\-1 < \frac{dy}{dx}\\\\[/tex]
note the inequality signs flipping when we apply the reciprocal to both sides, and when we multiply both sides by a negative value.
You should find that the same conclusion happens when we consider t < 0. Why? Because t < 0 becomes t^2 > 0 after we square both sides. The steps are the same as shown above.
So both t > 0 and t < 0 lead to [tex]-1 < \frac{dy}{dx}[/tex]
We can say that -1 is the lower bound of dy/dx. It never reaches -1 itself because t = 0 is not allowed.
We could say that
[tex]\displaystyle \lim_{t\to0}\left(2-\frac{3}{t^2+1}\right)=-1\\\\[/tex]
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To establish the upper bound, we consider what happens when t approaches either infinity.
If t approaches positive infinity, then,
[tex]\displaystyle L = \lim_{t\to\infty}\left(2-\frac{3}{t^2+1}\right)\\\\\\\displaystyle L = \lim_{t\to\infty}\left(\frac{2t^2-1}{t^2+1}\right)\\\\\\\displaystyle L = \lim_{t\to\infty}\left(\frac{2-\frac{1}{t^2}}{1+\frac{1}{t^2}}\right)\\\\\\\displaystyle L = \frac{2-0}{1+0}\\\\\\\displaystyle L = 2\\\\[/tex]
As t approaches infinity, the dy/dx value approaches L = 2 from below.
The same applies when t approaches negative infinity.
So we see that [tex]\frac{dy}{dx} < 2[/tex]
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Since [tex]-1 < \frac{dy}{dx} \text{ and } \frac{dy}{dx} < 2[/tex], those two inequalities combine into the compound inequality [tex]-1 < \frac{dy}{dx} < 2[/tex]
So dy/dx is bounded between -1 and 2, exclusive of either endpoint.
