The fourth term of a geometric progression is 4 and the seventh term is 32/125. Find the first term, the common ratio and the sum of the first nth terms. Hence, deduce the sum to infinity.​

Answers

Answer 1

Answer:

common ratio is 2/5

First term is  125/2

The sum of the first n terms is: [tex]S_n=\frac{125}{2} \, \frac{1-(2/5)^n}{3/5}[/tex]

The infinite sum is: [tex]S_\infty =\frac{625}{6}[/tex]

Step-by-step explanation:

The 4th term is 4, and the seventh term is 32/125 so we use the definition of nth term of a geometric sequence to create the following two equations:

[tex]a_4=a_1\,*\,r^{4-1} = a_1\,*\,r^3\\4=a_1\,*\,r^3\\and\\a_7=a_1\,*\,r^{7-1} = a_1\,*\,r^6\\\frac{32}{125} = a_1\,*\,r^6[/tex]

Now we divide a7 by a4 to get rid of a1 and work on determining the common ratio of the sequence:

[tex]\frac{a_7}{a_4} =\frac{8}{125} =\frac{a_1\,r^6}{a_1\,r^3} =r^3\\then\\r=\sqrt[3]{\frac{8}{125} } =\frac{2}{5}[/tex]

So, the common ratio is 2/5

we can now determine the first term:

[tex]a_4=4=a_1\,*\,(2/5)^3\\a_1=\frac{125*4}{8} =\frac{125}{2}[/tex]

The sum of the first n terms is given by the formula:

[tex]S_n=\frac{125}{2} \, \frac{1-(2/5)^n}{1-(2/5)} \\S_n=\frac{125}{2} \, \frac{1-(2/5)^n}{3/5}[/tex]

and therefore, the infinite sum is:

[tex]S_\infty = a_1\,\frac{1}{1-r} = \frac{125}{2} \,\frac{5}{3} =\frac{625}{6}[/tex]


Related Questions

Helpppppppp pleaseeeee

Answers

Answer:

108 cm^2

Step-by-step explanation:

A= 1/2 b×h

so

1/2 12×18

Please answer!! Will make brainliest (Photo is the question)

Answers

I think it’s either A or D

Rewrite the function f(x)=-4(x-3)^2+16 in the form f(x)=ax^2+bx+c

Answers

f(x)=-4(x-3)^2+16

first, simply each term

4x^2-24x+36+16

then add 36 to 16

4x^2-24x+52

Identify and write the hypothesis and the conclusion of the following conditional statement. "If I am running, then I am not awake."

Answers

Answers:

Hypothesis = "I am running"

Conclusion = "I am not awake"

===================================

Explanation:

All conditional statements are in the form "If P, then Q" where P and Q are placeholders for the hypothesis and conclusion respectively.

So you can say the basic format of a conditional is "If hypothesis, then conclusion".

what is the value of |3.25| ?

Answers

Answer:

3.25

Step-by-step explanation:

The answer is 3.25 because the absolute value of a number is basically that same number but it ALWAYS comes out positive.

Hope this helps :)

The value of |3.25 according to the question is; 3.25|.

The absolute value of a number is always positive irrespective of its initial sign polarity.

As such, since the number 3.25 is nested in the | | sign.

The absolute value is 3.25.

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Solve the following​

Answers

Answer:

Q1

|a-b| = b-a when a<b

Q2

104159/33000

Step-by-step explanation:

Q1

If a<b then a-b will always be negative.  To get the absolute value, we can take -(a-b) = -a+b = b-a.

Q2

Let x = 3.12789789789...

We isolate the repeating decimal to start after the decimal, so we multiply by 100.

100x = 312.789789789...

We want to multiply by 10 for each digit that repeats (in this case 3), to get the repeating part to the left of the decimal.

100000x = 312789.789789

Subtracting the two...

x(100000-100) = 312789.789789 - 312.789789

99900x = 312477

x = 312477/99000 = 104159/33000

Which finction results in f(2)=13?

Answers

Answer:

6.5

Step-by-step explanation:

plz mark brainlyest

Suppose a population has a mean weight of 180 pounds and a standard deviation of 25 pounds. A sample of 100 items is drawn from this population. What is the standard error of the​ mean?

Answers

Answer:

We are given:

μ=180,σ=25,n=100

Therefore the standard error of the mean is

2.5

Step-by-step explanation:

Determine the unknown side of the similar triangle.
A)
2
B)
3
4
D)
5

Answers

Answer : C) 4
Step by Step explanation:

Answer:

(C). 4

Step-by-step explanation:

Sides of the similar triangles are proportional.

if X ~ Y , then [tex]\frac{12}{6}[/tex] = [tex]\frac{8}{x}[/tex] ⇒ x = 4

What is the probability that a coin tossed in the air will land heads up? 25% 50% 75% 100%

Answers

Answer:

50%

Step-by-step explanation:

Answer: 50%

Step-by-step explanation: the normal probability is 1/2 sooo it translates to 50/100 which is 50%

If oranges cost 5 for 75cents how
many can you buy for $2.70?​

Answers

Answer:

15 oranges

Step-by-step explanation:

Only if im correct in assuming you get 5 oranges per 75 cents if not then im  not sure because im confused by the question

15 i think sorry i’m kinda confused

WHAT ARE THE X AND Y INTERCEPTS FOR THIS??

PLEASE ANSWERRRRR​

Answers

Answer:

Y-intercept = 0.4

X-intercept = 0.3

Step-by-step explanation:

Which of the following fractions is closest to
5/8

2/3
13/20
11/16

Answers

The closest fraction to 5/8 is 11/16

Rectangle ABCD is congruent to rectangle HGJK.

Rectangles A B C D and H G J K are shown. The length of A B is 11 inches. The length of K H is 18 inches.

What is the area of rectangle ABCD?

square inches

Answers

Answer:

It is 198

Step-by-step explanation:

(Width)(Height)

mutliply (11) times (18)

The area of rectangle ABCD is 198 square inches

The given parameters are:

[tex]\mathbf{AB = 11}[/tex]

[tex]\mathbf{KH = 18}[/tex]

Because the rectangles are congruent, then:

[tex]\mathbf{HG = AB = 11}[/tex]

[tex]\mathbf{KH = DA= 18}[/tex]

So, the area of rectangle ABCD is the product of side lengths AB and DA

So, we have:

[tex]\mathbf{Area = AB \times DA}[/tex]

Substitute values for AB and DA

[tex]\mathbf{Area = 11 \times 18}[/tex]

[tex]\mathbf{Area = 198}[/tex]

Hence, the area of rectangle ABCD is 198 square inches

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https://brainly.com/question/9655204

write the slope-intercept form of the equation of each line. identify the slopes y-intercept.

Answers

Answer:

1. 3,0,y=3x

2. -3/5, 1, y=-3/5x+1

3. -2/3, -4,y=-2/3x-4

4. 0, 4, y=4

5. 1, 5, y=x+5

6. 2, 0, y=2x

7. 4, 5, y=4x+5

8. 3/2, 4, y=3/2x+4

hopefully this helps :)

A system of equations is graphed on the coordinate plane.

y=−2x−4y=2x+4

What is the solution to the system of equations?

Answers

Answer:

No solution

Step-by-step explanation:

How long will it take an investment to double in value if the interest rate is 6% compounded continuously

Answers

Answer:

11.55 years

Step-by-step explanation:

Formula to calculate the final value when the money is compounded continuously is,

Final value = [tex]\text{(Present value)}.e^{rt}[/tex]

Here 'r' = rate of interest

t = duration for the investment

Let the money invested = $x

We have to find the duration in which the present value gets doubled.

Final value = $2x

Rate of interest = 6% per year ≈ 0.06

By substituting these values in the formula,

[tex]2x=x.e^{0.06t}[/tex]

[tex]2=e^{0.06t}[/tex]

ln(2) = [tex]\text{ln}e^{0.06t}[/tex]

0.693147 = 0.06t

t = 11.55 years

Therefore, invested amount will be doubled in 11.55 years.

Find the midpoint of the line segment with the given endpoints. R(-12, 8), S(6, 12)
1 (-3, 10) 2 (9, 2) 3 (10. -3) 4 (-9.2)​

Answers

Answer:

The answer is one.

Step-by-step explanation:

What is the GCF of x2 - 64?


Pls I really need help!

Answers

Answer:

The greatest common factor of x2-64 is 1

Step-by-step explanation:

Why are arithmetic sequences discrete data?

Answers

Answer:

If you take any number in the sequence then subtract it by the previous one, and the result is always the same or constant then it is an arithmetic sequence.

Step-by-step explanation:

Answer:

A sequence is a discrete structure used to represent an ordered list.

Step-by-step explanation:

Discrete values are values between the terms if the sequences are not included in the sequence. If you collect all the terms of the sequence into a set, that set will always be discrete, because there's only countably many of them, and every interval is uncountable. So in that sense, yes, sequences are discrete. A sequence is a discrete structure used to represent an ordered list. A sequence is a function from a subset of the set of integers (usually either the set {0,1,2,. . .} or {1,2, 3,. . .}to a set S. We use the notation an to denote the image of the integer n. We call an a term of the sequence.

choose the letter that corresponds to the correct answer​

Answers

Answer:

A

Step-by-step explanation:

PLEASE HELP AND BE REAL I WILL GIVE BRAINLY. Simplify 8.7+ (1.5) ²+4(3.5+6.2)-3.1 - 3.5

Answers

Answer:

43.15

Step-by-step explanation:

See attachment below

Determine if the following argument always applies, sometimes applies, or never applies. Provide at least 2 examples in your explanation.

"The sum of a number and its opposite is always 1."

Answers

Answer:

Never applies

Step-by-step explanation:

Given

Argument: The sum of a number and its opposite is always 1

Assume a positive number x

The opposite of the number is negative x (i.e. -x)

The sum of both numbers is:

[tex]Sum = x + (-x)[/tex]

Open Bracket

[tex]Sum = x -x[/tex]

[tex]Sum = 0[/tex]

Now, take for instance.

[tex]Number = 5[/tex]

Opposite would be

[tex]Opposite = -5[/tex]

Their sum is:

[tex]Sum = 5 + (-5)[/tex]

[tex]Sum = 5 -5[/tex]

[tex]Sum = 0[/tex]

Another instance is:

[tex]Number = -8[/tex]

Opposite would be

[tex]Opposite = 8[/tex]

Their sum is;

[tex]Sum = -8 + 8[/tex]

[tex]Sum = -0[/tex]

Hence, the argument never applies because the sum is never 1

which graph represents the function h(x)=2sin(x+pi/2)-1 ?

Answers

This graph represents the function h(x)=2sin(x+π/2)-1.

What is graph?

A graph can be defined as a pictorial representation or a diagram that represents data or values.

This graph represents the function h(x)=2sin(x+π/2)-1.

The range is the set of values that correspond with the domain.

Domain of graph: (−∞,∞),{x|x∈R}

Range of graph: [−3,1],{y|−3≤y≤1}

Use the form asin (bx−c)+d to find the amplitude, period, phase shift, and vertical shift.

Amplitude: 2

Period: 2π

Phase Shift: −π/2 (π/2 to the left)

Vertical Shift: −1

Learn more about graph

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#SPJ2

What is twenty six million four hundred five thousand twenty in standard form?

Answers

Answer:

26,405,020

Step-by-step explanation:

Answer:

26,405,020

Step-by-step explanation:

hope this helpssss

have a good nighttttt

here's the question​

Answers

The correct answer is:

5x-y>2 (3rd option)

Find the Lowest Score bounding upper 5%. The mean is 35 and the SD is 7

Answers

Answer:

get the mean deviation

<3 and <4 are vertical. m<3=5x+22 and m<4=7x+2. Find the measure of each angl.

Answers

Answer:

72°

Step-by-step explanation:

Vertical angles are congruent.

m∠3 = m∠4

7x + 2 = 5x + 22

2x = 20

x = 10

m∠3 = m∠4 = 72°

7/3 to 2 1/3
HELP ASAP PLSPLS !! :)

Answers

it is equal i believe!!!!

Find the value of 4+ (27 - 12.2) - 2.
19
5.5
3.5​

Answers

Answer:

5.5

Step-by-step explanation:

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