1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
mezya [45]
4 years ago
5

Which summation formula represents the series below?

Mathematics
1 answer:
Ber [7]4 years ago
8 0

Answer:

Step-by-step explanation:

The summation formula (  arithmetic sequence when the first terme is : A1 = 13

and the coomo diff is d= -4

Sn = n/2(A1 +An)

An = A1+(n-1)d

An = 13 +(n-1)(-4)

An = -4n +17

Sn = n/2(13+17-4n) = n/2(30-4n)

Sn = -2n² +15n

in this exercice : n =4      S4 = -2(4)² +15(4) = -32+60 = 28

verify : 13 + 9 + 5 + 1 =28   ......right

You might be interested in
If a window has a radius of 12 inches what is the circumference of the window
Crazy boy [7]
The circumference is 24 because the radius is half of the circumstance so 12 times 2 would be 24
5 0
4 years ago
Read 2 more answers
Write 39% as a fraction.
shutvik [7]
39/100 this is the answer of 39% as a fraction h
8 0
4 years ago
PLEASE PLEASE PLEASE HELP!!! I NEED MY GRADE TO BE UP BY BEFORE TOMORROW THESE ARE ALL THE POINTS I HAVE! 35 POINTS!!! Match the
hodyreva [135]

Answer:

1. A arithmetic sequence that starts at 1 and has a common difference of 3

  • (d) 1, 4, 7, 10, 13, ...

2. A geometric sequence that starts at 1 and has a common ratio of 3

  • (h) 1, 3, 9, 27, 81, ...

3. 15, 19, 23, 27, 31, ...

  • (b) arithmetic sequence; common difference of 4

4. 3, 27/3, 27, 243/3, 243, ...

  • (c) geometric sequence; common ratio of 3

5. -2, 16/4, -8, 16, -32, ...

  • (a) geometric sequence; common ratio of -2

6. 8, 40, 200, 1000, 5000, ...

  • (i) geometric sequence; common ratio of 5

7. 1432, 143.2, 14.32, 1.432, ...

  • (f) geometric sequence; common ratio of 0.1

8 0
4 years ago
Read 2 more answers
Please help find the value of x and show me steps so I can try to learn it!!
fiasKO [112]

Answer:

x = 30

Step-by-step explanation:

If we take a look at the given picture, we can see that both sides are almost completely identical, so they must almost have the same value.

Let us do the plug in. Keep in mind that the angle is obtuse, meaning over 90 degrees, and angle identical or lower than 90 is incorrect.

x=18

(x + 90)°

(18 + 90) = 108

True.

4x

4(18) = 72

False. Meaning the 18 would not work.

x = 22.5

(22.5 + 90) = 112.5

True.

4(22.5) = 90

False. Meaning that 22.5 does not work.

x = 30

(30+90) = 120

True.

4(30) = 120

True. Meaning that 30 is the answer and can work.

x = 54

(54+90) = 144

True.

4(54) = 216

False. Although the angle is larger than 90, 180 is a straight line, and we can see that the angles given are not straight lines or greater.

5 0
3 years ago
Lynn is making custom bricks. She combines 39 pounds of water and 48 pounds of brick dust in a mixing bucket. She spills 13 poun
ehidna [41]

Lynn mixes 39 pounds of water with 48 pounds of brick dust, so the mixture has a total weight of 39 + 48 = 87 pounds.

13 pounds are spilled during mixing, so she's left with 87 - 13 = 74 pounds to turn into bricks.

7 pounds are needed for 1 brick, so she can make 10 bricks because 7 • 10 = 70 and 7 • 11 = 77, and 70 < 74 < 77.

If she uses the mixture to make 10 bricks, she uses up 70 pounds of it, which leaves 4 pounds to be washed out.

5 0
3 years ago
Other questions:
  • Solve for x. x + 1/2 = 3/4 x = 1/4 x = -1/4 x = -1/2 x = 1/2
    13·2 answers
  • 2^30 + 2^30 + 2^30 + 2^30 =
    8·2 answers
  • Which polynomial is a quadratic trinomial?
    15·1 answer
  • Write the number described by 1 ten 16 ones.
    15·2 answers
  • Please help. I don't understand how to do number 14
    5·1 answer
  • Percents can be expressed as fractions and decimals. A percent means “out of 100,” so we can express 40% as the fraction 40⁄100.
    13·1 answer
  • I’ll give brainliest please help ASAP:)
    5·1 answer
  • I need help with this someone help me asap please
    5·2 answers
  • What is the product in simplest form −6/11⋅3/4
    15·2 answers
  • Q1): Which Statistical Method or Tool you will use to find out the following answers: A person who sells ice creams might want t
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!