Which of the following best describes the expression 12(x + 3)?

Consider the sequence {an}={3n+13n−3n3n+1}. Graph this sequence and use your graph to help you answer the following questions.

Fantom [35]

Part 1: You can simplify $a_n$ to

$\dfrac{3n+1}{3n}-\dfrac{3n}{3n+1} = \dfrac1{3n}+\dfrac1{3n+1}$

Presumably, the sequence starts at n = 1. It's easy to see that the sequence is strictly decreasing, since larger values of n make either fraction smaller.

(a) So, the sequence is bounded above by its first value,

$|a_n| \le a_1 = \dfrac13+\dfrac14 = \boxed{\dfrac7{12}}$

(b) And because both fractions in $a_n$ converge to 0, while remaining positive for any natural number n, the sequence is bounded below by 0,

$|a_n| \ge \boxed{0}$

(c) Finally, $a_n$ is bounded above and below, so it is a bounded sequence.

Part 2: Yes, $a_n$ is monotonic and strictly decreasing.

Part 3:

(a) I assume the choices are between convergent and divergent. Any monotonic and bounded sequence is convergent.

(b) Since $a_n$ is decreasing and bounded below by 0, its limit as n goes to infinity is 0.

Part 4:

(a) We have

$\displaystyle \lim_{n\to\infty} \frac{10n^2+1}{n^2+n} = \lim_{n\to\infty}10+\frac1{n^2}}{1+\frac1n} = 10$

and the (-1)ⁿ makes this limit alternate between -10 and 10. So the sequence is bounded but clearly not monotonic, and hence divergent.

(b) Taking the limit gives

$\displaystyle\lim_{n\to\infty}\frac{10n^3+1}{n^2+n} = \lim_{n\to\infty}\frac{10+\frac1{n^3}}{\frac1n+\frac1{n^2}} = \infty$

so the sequence is unbounded and divergent. It should also be easy to see or establish that the sequence is strictly increasing and thus monotonic.

For the next three, I'm guessing the options here are something to the effect of "does", "may", or "does not".

(c) may : the sequence in (a) demonstrates that a bounded sequence need not converge

(d) does not : a monotonic sequence has to be bounded in order to converge, otherwise it grows to ± infinity.

(e) does : this is true and is known as the monotone convergence theorem.

5 0

3 years ago

If y=26−(3x+2), then x = ?

Anna71 [15]

Answer:

-1/3y +8 = x

Step-by-step explanation:

y=26−(3x+2)

Distribute

y = 26 -3x-2

Combine like terms

y = 24 -3x

Subtract 24 from each side

y -24 = -3x

Divide each side by -3

y / -3 -24/-3 = -3x/-3

-1/3y +8 = x

3 0

3 years ago

2. How are rectangles and paralelograms diferent?

Gwar [14]

Answer:

A parallelogram has two parallel pairs of opposite sides. A rectangle has two pairs of opposite sides parallel, and four right angles. It is also a parallelogram, since it has two pairs of parallel sides.

5 0

3 years ago

The caller times at a customer service center has an exponential distribution with an average of 22 seconds. Find the probabilit

jenyasd209 [6]

Answer:

The probability that a randomly selected call time will be less than 30 seconds is 0.7443.

Step-by-step explanation:

We are given that the caller times at a customer service center has an exponential distribution with an average of 22 seconds.

Let X = caller times at a customer service center

The probability distribution (pdf) of the exponential distribution is given by;

$f(x) = \lambda e^{-\lambda x} ; x > 0$

Here, $\lambda$ = exponential parameter

Now, the mean of the exponential distribution is given by;

Mean = $\frac{1}{\lambda}$

So, $22=\frac{1}{\lambda}$ ⇒ $\lambda=\frac{1}{22}$

SO, X ~ Exp( $\lambda=\frac{1}{22}$ )

To find the given probability we will use cumulative distribution function (cdf) of the exponential distribution, i.e;

$P(X\leq x) = 1 - e^{-\lambda x}$ ; x > 0

Now, the probability that a randomly selected call time will be less than 30 seconds is given by = P(X < 30 seconds)

P(X < 30) = $1 - e^{-\frac{1}{22} \times 30}$

= 1 - 0.2557

= 0.7443

7 0

3 years ago

Angle G and H are vertical angles. If angle G is 45 degrees and angle H is 2x degrees, what is the value of x?

Veseljchak [2.6K]

Answer:

x = 22.5

Step-by-step explanation:

Vertical angles are congruent by the vertical angles theorem. Therefore is angle G is 45 degrees, then that means that angle H must be 45 degrees as well.

The value of x can be found by making the expression that represents angle H (2x) equal to 45 in an equation to solve for x.

2x = 45

Divide both sides by 2.

x = 22.5

6 0

3 years ago