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....
Write an eighth-degree polynomial in factored form that is decreasing at both ends , has a single root at -2, a double root at 3 and 0 and triple root at -1
Answer:
Step-by-step explanation:
y = -1(x + 2)(x - 3)(x - 3)(x + 0)(x + 0)(x + 1)(x + 1)(x + 1)
The 8 degree polynomial for the given roots can be written as p(x) = x⁸ - x⁷- 12x⁶ - 4x⁵ + 30x⁴ + 51x³ + 18x².
What is factor theorem?The factor theorem states that for a polynomial p(x) if there exists a real number a such that p(a) = 0, then (x - a) is one of the factors of p(x).
The roots of the polynomial are given as follows,
Number of roots at -2 = 1
Number of roots at 3 = 2
Number of roots at 0 = 2
And, number of roots at -1 = 3.
Now, the polynomial can be written using factor theorem as,
p(x) = x²(x + 2)(x - 3)²(x + 1)³
= x²(x + 2)(x²- 6x + 9)(x³ + 3x² + 3x + 1)
= x⁸ - x⁷- 12x⁶ - 4x⁵ + 30x⁴ + 51x³ + 18x²
Hence, the polynomial for given roots can be written as p(x) = x⁸ - x⁷- 12x⁶ - 4x⁵ + 30x⁴ + 51x³ + 18x².
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What's the length of QR?
Answer:
using the pithagerum therom
a² + b² = c²
this formula is to find the side of your triangle with 2 sides already known
the answer is A) 17.7
Mr. Stansbury went grocery shopping on Tuesday and bought 4 pounds of oranges for $10.88. What is the unit price per ounce?
Answer:
0.68
Step-by-step explanation:
Help help help help help math math
Step-by-step explanation:
again, a line cutting through 2 parallel lines must have the exact same angles with both of them. otherwise they would not be parallel.
therefore, both angles must be identical
3x + 2 = 2x + 6
x = 4
Does anyone know how to solve this
The answer is B but can anyone explain why
Answer:
B. (0,-1)
Step-by-step explanation:
see.. i'm not rude.... :/
Find the center and radius of the circle with the equation: (x=5)2 +(4-2)3-25
Answer:
center = (5 ,-3) and radius = 5
Step-by-step explanation:
Liz has 72 stamps in her stamp collection. Risa, who just started her collection, has 9 stamps. Liz’s collection is how many times larger than Risa’s? Choose the answer that has the correct equation AND the correct solution to the equation.
9x = 72; x = 8 times as many stamps
9 + x = 72; x = 63 times as many stamps
9x = 72; x = 7 times as many stamps
72x = 9; x = 8 times as many stamps
Answer:
9x = 72; x = 8 times as many stamps
Step-by-step explanation:
Answer:
9×=72;×=8 times as many stamps
How do I subtract fractions? Please explain step by step to get marked!
Answer:
Explained below :)
(I tried my best, sorry if it doesn't make sense.)
Step-by-step explanation:
Example: 1/4 - 1/8= ?
1: Find the common denominator (bottom number)
2: If the common denominator is 8 then you multiply 1/4 by 2/2 to get the denominator of 8. If you needed then you can multiply the other fraction to get the same denominator.
3: Once you get multiply that then you get 2/8 -1/8.
4: Subtract the numerator (top number) 1
5: Keep the numerator (8)
6: Your answer would be 1/8
help me out guys !!!!!!
Answer:
[tex]2\sqrt[3]{5}[/tex]
Step-by-step explanation:
40 = 8 x 5 and 8 is the cube of 2, so 2 goes on the outside but 5 can't be simplified
As an improper fraction simplified
Answer:
82/63
Step-by-step explanation:
The sum can be found using the formula ...
[tex]\dfrac{a}{b}+\dfrac{c}{d} =\dfrac{ad+bc}{bd}[/tex]
For the given fractions, the sum is ...
[tex]\dfrac{6}{7}+\dfrac{4}{9} =\dfrac{6\cdot9+7\cdot4}{7\cdot9}=\dfrac{54+28}{63}=\boxed{\dfrac{82}{63}}[/tex]
_____
Additional comment
When the denominators have no common factor, the least common denominator is their product, as here.
Answer:
For this question, you can make the denominators the same to get the answer.
LCM of 7 and 9 = 63
[tex]\frac{6}{7} + \frac{4}{9} = \frac{54}{63} + \frac{28}{63} \\[/tex]
= [tex]\frac{82}{63}[/tex]
= 1[tex]\frac{19}{63}[/tex]
What is the slope of the line throught (-9, 6) and (-3, 9)?
Answer:
The slope is 1/2
Step-by-step explanation:
To find slope, use the formula y2-y1/x2-x1
Plug the points in and solve.
9-6/(-3)-(-9)
3/-3+9
3/6
1/2
Answer:
[tex]m=\frac{1}{2}[/tex]
Step-by-step explanation:
Formula:
[tex]\boxed{\frac{y_2-y_1}{x_2-x_1}}[/tex]
Assign the points as [tex]x_1[/tex], [tex]x_2[/tex], and, [tex]y_1[/tex], [tex]y_2[/tex]
[tex](-9 = x_1, 6=y_1) \:\:\:\:(-3=x_2, 9=y_2)[/tex]
Plug these points into the formula; solve
[tex]\frac{y_2-y_1}{x_2-x_1}\\\\=\frac{9-6}{-3-(-9)}\\=\frac{1}{2}[/tex]
[tex]\bold{m=\frac{1}{2}}[/tex]
Therefore, [tex]\frac{1}{2}[/tex] is the slope of the line through [tex](-9, 6)[/tex] and [tex](-3, 9)[/tex].
Two parallel lines are cut by a transversal, as shown below. Solve for b. Then explain your reasoning.
Answer:
b = 14
Step-by-step explanation:
Since both angles are diagonal each other, they are equal to each other.
5b = b + 56
-b -b (subtract b from both sides)
4b = 56
4 4 (divide both sides by 4 to solve for b)
b = 14
The price of gas on Wednesday was 52.03/gallon. On Friday, the price of gas was $2.26. What is the percent change in the price of gas?
Answer:
Percent change in the price of gas is [tex]9.85\%[/tex]
Step-by-step explanation:
Percentage change equals the change in value divided by the absolute value of the original value, multiplied by .
[tex]\text { Percentage Change }=\frac{\Delta V}{\left|V_{1}\right|} \times 100[/tex]
Here
[tex]\Delta V=2.26-2.03\\\\=0.23\$/gallon[/tex]
[tex]V_{1}=2.03\$/gallon[/tex]
The percent change in the price of gas
[tex]=\frac{0.23}{2.03} \times100\\\\=9.85\%[/tex]
Percent change in the price of gas is [tex]9.85\%[/tex]
Use the graph method to solve the system of Linear equations:
2x + y = 3 and x + y = 3
A) (-1.5, 0)
B) (0, -1.5)
C) (0,3)
D) (3, 0)
Helpppp pleaseeee ????
Answer:
LQ = 54
Median = 69
UQ = 94
Step-by-step explanation:
This list is already sorted for you, so you don't need to worry about that, otherwise you would need to sort the numbers in ascending order. To find the median, we do [tex]\frac{n+1}{2}[/tex], where n is the amount of numbers. This gives us 4, so the median is at position 4, so the median is 69. The lower quartile is simply [tex]\frac{n+1}{4}[/tex], so 2, so the lower quartile is 54. The upper quartile is [tex]\frac{n+1}{2} X 3[/tex], so 6, so the upper quartile is 94.
Which of the following equations has only one solution? A. x^2 -8 x + 16 = 0 B. x(x - 1) = 8 C. x^2 = 16
[tex]\\\\\\x^2 -8x +16 = 0\\\\\implies x^2 - 2(4) + 4^2 =0\\\\\implies (x-4)^2 =0\\\\\implies x -4 =0\\\\\implies x =4\\\\\text{This equation has only one solution.}[/tex]
anyone please help this hard
Answer:
a. 6
b. 21
c. 78
d. 13.5
e. 14
f. 24
Hope that helps!
Someone please help me!
If you put $1,000 in a savings account that yields an 7% annual rate of interest that is compounded weekly,
a
how much would that be worth in 25 weeks (round to the nearest dollar)?
(Select the best choice below.)
O A. $1,040
O B. $1,034
O C. $1,043
OD. $1,025
Please show work! Thank you
Answer:
Answer B- 1034
7% annual rate is 70. divide by 52 (total amount of weeks in a year) =1.35. 1.35 × 25=33.75 rounded up 34. 1000+34=1034
A 25-inch television has a screen that is 15 inches high. How wide is the screen?
inches
Answer:
20 inches
Step-by-step explanation:
Use the Pythagorean Theorem.
[tex]a^2 + b^2 = c^2\\15^2 + b^2 = 25^2\\225 + b^2 = 625\\b^2 = 400\\b = \sqrt{400} \\b = 20[/tex]
If you had a choice between playing golf or going to the movies and you chose to go to the movies, what is the opportunity cost of your decision.
The potential gain that could have come with golfing
Step-by-step explanation:
Opportunity cost is the loss of something you could have gotten from the choice you didn't go with. so I'm this case, the opportunity cost of chosing the movies is what you missed out on by not going golfing.
A set of data has a correlation coefficient of 0.05. What is the best way to describe the correlation of the data set
A strong negative correlation
B strong positive correlation
C weak postive correlation
D little or no correlation
what is 4 divided by 8
Answer:
0.4 or 2
Step-by-step explanati
that easy
30=2y+16 simplify your answer as much as possible
Answer:
y=7
Step-by-step explanation:
Write the equation in standard form.
y + 7 = -3 (x + 1)
Standard form = ax+by+c=0
= Writing the given eq. in standard form =
= y+7=-3x-3
= 3x+y+7+3=0
= 3x+y+10=0
What is the solution to the equation 8b+32=104?
Answer: the answer is b=9
Step-by-step explanation:
Step 1: Subtract 32 from both sides.
104-32= 72
Step 2: Divide both sides by 8.
72 divided by 8 is 9
therefor the answer is 9
Find the number that makes the ratio equivalent to 9:1
Answer has to end with :8
What is the volume of this rectangular prism?
1
cm
2
4 cm
ola
3
cm
cm3. Because this is hard
Step-by-step explanation:
Volume=length*width*height
V = (3/2)*(4)*(1/2)
= 12/4 = 3cm^3
What is the value of (-5)2?
Answer:
-10
Step-by-step explanation:
when a number Inside of parentheses is close to another number (like being near a fireplace trying to say warm) it means to multiply :3 !
Example: (3)2=6 6(6)=36
in our case it is (-5)2 So was ist -5 x 2? -10
hope this helped!
for some extra practice to check your knowledge, what is (-3+-2)2 ?
Which expression is equivalent to 1/4 (5x + 6)?
The expression which is equivalent to 1/4 (5x + 6) is; Choice A: {5(1/4)x} + {6(1/4)x}.
According to the question:
We are required to determine an expression which is equivalent to 1/4 (5x + 6).In a bid to expand the expression; we must multiply each term in the parenthesis by (1/4);
In essence; we have;
{5(1/4)x} + {6(1/4)x}Read more on multiplication;
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