Question

A pyramid of logs has 2 logs in the top row, 4 logs in the second row from the top, 6 logs in the third row from the top, and so on, until there are 200 logs in the bottom row. ​ Is the pattern an arithmetic sequence?​ Identify a and d.​ Write the 50th term of the sequence.​ Find the total number of logs in the first 10 rows.​

Answer 1

Answer:

1) Is the pattern an arithmetic sequence?​

Yes it is

2)Identify a and d.​

a = First term = 2

d = Common difference = 2

3) Write the 50th term of the sequence.​

50th term = 100

4) Find the total number of logs in the first 10 rows.​

= 1010 logs

Step-by-step explanation:

Is the pattern an arithmetic sequence?​

Yes it is

2) Identify a and d.​

A pyramid of logs has 2 logs in the top row, 4 logs in the second row from the top, 6 logs in the third row from the top, and so on,

The formula for arithmetic sequence =

an = a+ (n - 1)d

a = First term

d = Common difference

For the above question:

a = 2

d = Second term - First term

= 4 - 2

d = 2

3) Write the 50th term of the sequence.​

Using the formula for arithmetic sequence

an = a+ (n - 1)d

a = 2

n = 50

d = 2

a50 = 2 + (50 - 1)2

= 2 + (49)2

= 2 + 98

= 100

The 50th term = 100

4)Find the total number of logs in the first 10 rows.​

Sum of first n terms = n/2(a + l)

n = 10

a = first term = 2

We are told that there are 200 logs in the bottom row, hence:

l = last term = 200 logs

Hence,

Sn = 10/2×[ (2 + 200

= 5(202)

= 1010 logs