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
Snezhnost [94]
3 years ago
14

the sum of the first six terms of a geometric series is 21/16 . if the common ratio is -1/2 , what is the first term?

Mathematics
1 answer:
Oksanka [162]3 years ago
8 0

Answer:

-84

Step-by-step explanation:

The formula for the nth term of a geometric progression is

Un = ar^n- 1

The sum of the first six terms of a geometric series (U6) = 21/16

Common ratio = -1/2 ,

a = First term ??

21/16 = a × (-1/2 )^6- 1

21/16 = a ×(-2^-1)^5

21/16 = a × -2^-6

Cross Multiply

16 × a × -2^-6 = 21

a = 21/16 × -2^-6

a = 21/16 ×- 1/2⁶

a = 21/16 × -1/64

a = 21 ÷(-1/4)

a = 21 × -4

a = -84

The first term = 84

You might be interested in
The tables show the number of plants and the number of flowers. Which table represents a proportional relationship?
Usimov [2.4K]


 the last one because 7*3=21 14*3=42 and 21*3=63
4 0
3 years ago
Find the midpoint of the line segment whose endpoints are (3, 10) and (7, 8).
Stels [109]

Answer:

Option 2 is correct.

Step-by-step explanation:

Given the coordinates of lines segment (3, 10) and (7, 8). we have to find the mid-point of given line segment.

Mid-point formula states that if (x_1,y_1) and (x_2,y_2) are the coordinates of end points of line segment then the coordinates of mid-point are

(\frac{x_1+x_2}{2},\frac{y_1+y_2}{2})

∴ Coordinates of mid-point of line segment joining the points          (3, 10) and (7, 8) are

(\frac{3+7}{2},\frac{10+8}{2})=(\frac{10}{2},\frac{18}{2})=(5,9)

Hence, option 2 is correct.

6 0
3 years ago
Read 2 more answers
Which percentage is equivalent to 14/25
Leviafan [203]

46% is equal to 14/25

14/25 is equal to 46/100 (multiply 14/25 times 4/4) and that is 46%

5 0
2 years ago
Read 2 more answers
A car wash cost $7. How many car washes would you be able to purchase for $49. using table
Over [174]
7, 14, 21, 28, 35, 42, 49... 7 cars will need. to be washed to reach $49
4 0
3 years ago
Read 2 more answers
What are the first 5 numbers of pie?​
DIA [1.3K]

The answer is:

3.14159

8 0
4 years ago
Read 2 more answers
Other questions:
  • Hi everyone!! I just need the o e that is circled in red, that all. Thank you all in advance!!!
    9·1 answer
  • Suppose that a is a nonzero constant for which the equation ax^2+20x+7=0 has only one solution. find this solution.
    15·1 answer
  • Simplify fully<br> 13/2x-5/x
    14·2 answers
  • Mr. Davis has 15 students in his class. He wants to send 3 of his students to pick up books for the class. How many different co
    6·1 answer
  • HELP PLEASE???<br> !!!<br> ????<br> ???<br> ??
    10·1 answer
  • What is the quotient of 1/7 divided 2
    10·2 answers
  • Which situation represents a proportional relationship?
    15·2 answers
  • Steve borrows $20,000 for a car at an annual interest rate of 8.5% for 5 years. What is the balance of his loan?
    9·1 answer
  • Help me now before i push you in ragdoll engine jk oh no oh pls help me istg- i love you
    12·1 answer
  • Amanda's family is taking a road trip. Their car can travel no more than 352 miles without needing to refill the gas tank. They
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!