Please help me solve this

Notice that

a + ar³ + ar⁶ + ar⁹ + ... = a + r³ (a + ar³ + ar⁶ + ...)

but the grouped sum on the right side is the same as the sum on the left side. This means that, if the sum we want to compute

a + ar³ + ar⁶ + ar⁹ + ...

converges to S, then

S = a + r³ S

Solve for S :

S - r³ S = a

(1 - r³) S = a

S = a/(1 - r³)

Similarly, knowing the value of the first sum, we have

a + ar + ar² + ar³ + ... = a + r (a + ar + ar² + ...)

but we know

a + ar + ar² + ... = 15

so

15 = a + 15r

and knowing the value of the second sum, we have

a + ar² + ar⁴ + ... = a + r² (a + ar² + ar⁴ + ...)

so

9 = a + 9r²

Solve these two equations for a and r :

15 = a + 15r   ⇒   a = 15 - 15r

9 = a + 9r²   ⇒   9 = 15 - 15r + 9r²   ⇒   3r² - 5r + 2 = (3r - 2) (r - 1) = 0

⇒   r = 2/3 or r = 1

We cannot have r = 1, since that would mean

a + a + a + ... = 15

since the left side is adding infinitely many copies of some constant; such a sum can never converge to a finite number. So it must be that r = 2/3, and it follows that a = 15 - 15 (2/3) = 5.

Then the sum we want has a value of

S = 5/(1 - (2/3))³ = 135/19

Answer:

Step-by-step explanation:

  a + ar¹ + ar² + ar³ + ... = 15       #1

r(a + ar¹ + ar² + ar³ + ...) = 15r

       ar¹ + ar² + ar³ + ... = 15r      #2

subtract #2 from #1

a = 15 - 15r

     a + ar² + ar⁴ + ar⁶ + ... = 9         #3

r²(a + ar² + ar⁴ + ar⁶ + ... )= 9r²

         ar² + ar⁴ + ar⁶ + ... = 9r²       #4

subtract #4 from #3

a = 9 - 9r²

15 - 15r = 9 - 9r²

9r² - 15r + 6 = 0

3r² - 5r + 2 = 0

r = (5 ±√(5² - 4(3)(2))) / (2(3)

r = (5 ± 1) / 6

r = 1

or

r = 4/6 = 2/3

if r = 1 then a = 15 - 15(1) = 0 and a series of zeros added together can never equal 15 so r = 2/3 must be true.

a = 15 - 15(2/3) = 5

   a + ar³ + ar⁶ + ar⁹ + ... = C           #5

r³(a + ar³ + ar⁶ + ar⁹ + ...) = Cr³

         ar³ + ar⁶ + ar⁹ + ... = Cr³          #6

subtract #6 from #5

a = C - Cr³

a = C(1 - r³)

C = a/(1 - r³)

C = 5/(1 - (2/3)³)

C = 5/(1 - 8/27)

C = 5/(19/27)

C = 5(27/19)

C = 135/19 = 7.1052631578947368....

Answer:

the asnswer is -67463 to the power of 4

Step-by-step explanation:

Answer:

x + 9 = 32

Step-by-step explanation:

answer for x is 32 - 9 = 23

Using proportions, it is found that the expression that shows the total height of Grandma Maude’s cake is:

[tex]t = 12x^5 + 5x^3 - 2x[/tex]

The rule of three is:

1 layer - [tex]2 + 3x^2[/tex] cm

[tex]4x^3 - x[/tex] layers - t cm

Applying cross multiplication:

[tex]t = (4x^3 - x)(2 + 3x^2) = 12x^5 + 5x^3 - 2x[/tex]

To learn more about proportions, you can take a look at https://brainly.com/question/24372153

Answer:

12x5 + 5x3 – 2x cm

Step-by-step explanation:

Answer:

$245,000

Step-by-step explanation:

Let the intial cost = x

[tex]100\% + 36\% = 136\% = 1.36[/tex]

[tex]1.36x = 333200[/tex]

[tex]x = \frac{333200}{1.36} [/tex]

[tex]x = 245000[/tex]

Answer:

......

Step-by-step explanation:

The equation has the same solution as w / 3.9 = 3 is w+0.6=1.9

Given:

w / 3.9 = 3

cross multiply

w × 3 = 3.9

3w = 3.9

divide both sides by 3

w = 3.9 / 3

w = 1.3

Check all that applies

A. w+0.6=1.9

w = 1.9 - 0.6

w = 1.3

B. w-0.6 = 11.1

w = 11.1 + 0.6

w = 11.7

C. w+1.03=2.93

w = 2.93 - 1.03

w = 1.9

D. w-1.03=8.24

w = 8.24 + 1.03

w = 9.27

Therefore, the equation has the same solution as w / 3.9 = 3 is w+0.6=1.9

Learn more about equation:

https://brainly.com/question/2972832

Answer:

the quantity seven minus three divided by two

Step-by-step explanation:

its math

Answer:

3/2x

Step-by-step explanation:

−

2

3

x

−

4

9

=

3

2

x

Answer:

y = 21

Step-by-step explanation:

2z ÷ [z – (z – 4)]

Sub z=8 into the expression

2(8) ÷ [8 – (8 – 4)] = 16 ÷ 4

                             = 4

I assume a is a constant. If tan(x) = exp(at) (where exp(x) means eˣ), then differentiating both sides with respect to t gives

sec²(x) dx/dt = a exp(at)

Recall that

sec²(x) = 1 + tan²(x)

Then we have

(1 + tan²(x)) dx/dt = a exp(at)

(1 + exp(2at)) dx/dt = a exp(at)

dx/dt = a exp(at) / (1 + exp(2at))

If exp(y) = 1 + exp(2at), then differentiating with respect to t yields

exp(y) dy/dt = 2a exp(2at)

(1 + exp(2at)) dy/dt = 2a exp(2at)

dy/dt = 2a exp(2at) / (1 + exp(2at))

By the chain rule,

dy/dx = dy/dt • dt/dx = (dy/dt) / (dx/dt)

Then the first derivative is

dy/dx = (2a exp(2at) / (1 + exp(2at))) / (a exp(at) / (1 + exp(2at))

dy/dx = (2a exp(2at)) / (a exp(at))

dy/dx = 2 exp(at)

Since dy/dx is a function of t, if we differentiate dy/dx with respect to x, we have to use the chain rule again. Suppose we write

dy/dx = f(t)

By the chain rule, the derivative is

d²y/dx² = df/dx

d²y/dx² = df/dt • dt/dx

d²y/dx² = (df/dt) / (dx/dt)

d²y/dx² = 2a exp(at) / (a exp(at) / (1 + exp(2at)))

d²y/dx² = 2 (1 + exp(2at))

Answer:

A = 80π

Step-by-step explanation:

Area of a circle is A = πr²

Area of the the largest circle - Area of the smaller circle = the shaded part.

Largest circle    -    Area of the smaller circle   = Shaded part of circle

A  = π(12)²         -     A = π(8)²

    144π            -      64π                           =        80π

Answer:

$225

Step-by-step explanation:

$120 for 2 4-hour shifts, $120 in 8 hours

$15 every 1 hour

Money for 15 hours: 15 x 15 = $225

The office clerk earns $225 for 15 hour of work .

The formula of the unitary method is to find the value of a single unit and then multiply the value of a single unit to the number of units to get the necessary value.

According to the question

An office clerk earns $120 for two 4-hour work shifts.

i.e

In 2 * 4-hour work shifts office clerk  earns = $120

or

In 8 hour work shifts office clerk earns = $120

Now ,

By using unitary method

In 1 hour  work shifts office clerk earns = $[tex]\frac{120}{8}[/tex]

                                                                = $15

Therefore, for 15 hours of work shifts office clerk earns =  $15 * 15

                                                                                          = $225

Hence, The office clerk earns $225 for 15 hour of work .

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#SPJ2

Answer:

1280

Step-by-step explanation:

look at the 6 in the number

is it 4 or less

or is it 5 or more

as the number is 6 ( more than 5)

then you are going to add 1 to the tens

so the final answer is 1280

I really hope this helps and have a great day

Answer: 67°.

Step-by-step explanation:

1) m∠PMR=m∠LMN=3x+19°;

2) m∠LMN+m∠LMP=180°, it can be written as 3x+19+9x-31=180;

3) if to solve the equation 3x+19+9x-31=180, then x=16;

4) m∠PMR=3x+19=48+19=67°.

Find x

Linear pairs are supplementary

So

opposite angles are equal

Answer:

he is incorrect.

no one can run for 5 miles everyday.

if so, my man atteo is a legend.

Answer:

i think D. 4x4x4 = 64 is answer

Step-by-step explanation:

4³ = 4×4×4 = 64

The question relates to the total number of pairs of feet ducks and a pigs

are known to have.

Reasons:

The length of the group of ducks and pigs = 40 feet

Number of ducks = Twice the number of pigs

Let x represent the number of pigs, and let y represent the number of ducks, we have;

y = 2 × x

4·x + 2·y = 40

Which gives;

4·x + 2 × (2·x) = 40

8·x = 40

x = 40 ÷ 8 = 5

y = 2 × x

Therefore;

y = 2 × 5 = 10

Learn more about solving word problems in mathematics here:

https://brainly.com/question/25272317

Answer:

19

Step-by-step explanation:

In the first number, they add three and that number is repeated.

To further explain, the series would continue like this:

7, 10, 10, 13, 16, 16, 19, 22, 22...

Hope this helps! Brainliest would be appreciated!

Answer:

Step-by-step explanation:

Equilateral Triangle

Regular Hexagon

Answer: The answer is 8.91.

Answer : 8.91

Step - by - step explanation :

Sometimes if a question is to big for you - it's best to start off small . . .

4.60 + 3.28 = 7.88

7.88 + 1.03 = 8.91

Answer: 11/15 hours

Step-by-step explanation:

Find LCD (lowest common denominator)

1/3=5/15

2/5=6/15

6/15+5/15=11/15 hours or 44 minutes

Answer:

I don't know sorry

Answer:

25cm^2

Step-by-step explanation:

A square has 4 equal sides so each side will be 20/4 = 5cm

Easily calculate the area by taking 5 x 5 = 25cm^2

Answer:

1.64×10⁷ km

Step-by-step explanation:

We know this is a triangle rectangle, so we apply the Pythagorean Theorem

QR=sqrt(PR²+PQ²)

Solving it, we will encounter in

sqrt(2.56×10¹⁴+1.296×10¹³)

to solve it, we need to bring the two numbers at the same power of ten, so we move 1.296 of one place to the left:

sqrt(2.56×10¹⁴+0.1296×10¹⁴)

we can now add the two numbers:

sqrt(2.6896×10¹⁴)

to solve this, we do the square root of 2.6896 and divide 14 by two (the index of the root is 2, so for roots' properties we can divide 14 by 2 - the index)

which gives us

1.64×10⁷

Answer:

On a number line, -4 is located to the right of -5

Step-by-step explanation:

Answer:

On a number line, -4 is located to the right of -5.

Step-by-step explanation:

this is correct, also I don't take credit for it the person above me is the original. :)

We are given –

We know that–

[tex]\qquad[/tex][tex] \purple{\bf\longrightarrow Area_{(Rectangular)} = Length \times Breadth} [/tex]

[tex]\qquad[/tex][tex] \sf \longrightarrow 92 = 11.5 \times Breadth [/tex]

[tex]\qquad[/tex][tex] \sf \longrightarrow Breadth = \cancel{\dfrac{92}{11.5}}[/tex]

[tex]\qquad[/tex][tex] \purple{\bf \longrightarrow Breadth = 8 \: mm}[/tex]

Now, Perimeter of rectangular –

[tex]\qquad[/tex][tex] \pink{\bf \longrightarrow Perimeter _{(Rectangular) } = 2( Length + Breadth) }[/tex]

[tex]\qquad[/tex][tex] \sf \longrightarrow Perimeter _{(Rectangular) }= 2( 11.5 +8) [/tex]

[tex]\qquad[/tex][tex] \sf \longrightarrow Perimeter _{(Rectangular) } = 2 \times 19.5[/tex]

[tex]\qquad[/tex][tex]\pink{ \bf \longrightarrow Perimeter _{(Rectangular) } = 39\: mm}[/tex]

_______________________________________

Answer:

Step-by-step explanation:

In this question we are given with ,

And we're asked to find the perimeter of rectangle .

Solution : -

We know that ,

[tex] \pink{ \boxed{\sf{Area \: of \: rectangle = L × W}}}[/tex]

Where ,

So from this formula we can find the width of rectangle and equating it with 92 ( because 92 is the given area ) . Substituting value of length :

[tex] \longmapsto \: 11.5 \times W = 92[/tex]

Step 1 : Multiplying 11.5 and W :

[tex] \longmapsto \: 11.5W = 92[/tex]

Step 2 : Dividing by 11.5 on both side :

[tex] \longmapsto \: \frac{ \cancel{11.5}W}{ \cancel{ 11.5}} = \frac{92}{11.5} [/tex]

On further calculations we get :

[tex] \longmapsto \: W = \cancel{\frac{920}{115} }[/tex]

Step 3 : By cancelling 920 by 115 we get :

[tex] \longmapsto \: \purple{\boxed{ \bold{W = 8 \: mm}}}[/tex]

We know that ,

[tex] \blue{ \boxed{ \sf{Perimeter \: of \: rectangle = 2 ( L +W )}}}[/tex]

Where ,

Substituting values in formula :

[tex] \longrightarrow \: 2(11.5 + 8)[/tex]

Step 1 : Solving parenthesis :

[tex] \longrightarrow \: 2(19.5)[/tex]

Step 2 : Multiplying 2 with 19.5 :

[tex] \longrightarrow \: \green{\boxed{ \bold{39 \: mm}}}[/tex]

Answer:

false

Step-by-step explanation:

bacteria are bigger and more complex than viruses.