Geometric sequences

2010004902

Level:

The following numbers form a geometric sequence. The fourth term satisfies

a < 0

. Find

x

7, x, \frac{1}{7}, a

- 1

1

- 7

- \frac{1}{7}

2010004908

Level:

At which term does the geometric sequence

(\frac{1}{2187}, \frac{1}{729}, \frac{1}{243}, \frac{1}{81}, \dots)

begin to have natural values?

8

9

7

10

2010004909

Level:

At which term does the geometric sequence

(\frac{1}{4096}, \frac{1}{1024}, \frac{1}{256}, \frac{1}{64}, \dots)

begin to have natural values?

7

8

6

9

2010004910

Level:

At which term does the geometric sequence

(2187, 729, 243, 81, \dots)

begin to have values less than

1

9

8

7

10

2010004911

Level:

At which term does the geometric sequence

(4096, 1024, 256, 64, \dots)

begin to have values less than

1

8

7

6

9

2010004912

Level:

At which term does the geometric sequence

(10; 12; 14.4; 17.28; \dots)

exceed

100

? (Use a calculator.)

14

13

12

15

2010004913

Level:

At which term does the geometric sequence

(8; 10; 12.5; 15.625; \dots)

exceed

80

? (Use a calculator.)

12

11

13

14

2010004914

Level:

Identify the real number

x

which converts the numbers

a_{1} = 3^{x - 6}

a_{2} = 1

and

a_{3} = 3^{x}

into three consecutive terms of a geometric series.

x = 3

x = 1

x = \log 3

x = 10

x = 100

2010004915

Level:

Consider the geometric sequence with

a_{2} = 50

and

a_{3} = 10

. Find the sum of the first four terms.

312

62.4

66

315

312.4

2010005501

Level:

The sum of the first and the second term of a geometric sequence is

2

, the sum of the third and the fourth term is

18

and the common ratio is negative. Find the first term.

- 1

1

2

\frac{1}{2}

- 2

« first
‹ previous
…
2
3
4
5
6
7
8
9
10
…
next ›
last »

2010004902

2010004908

2010004909

2010004910

2010004911

2010004912

2010004913

2010004914

2010004915

2010005501

Events

Akce

Interests

Zajímavosti

About portal

O portálu