Sunday

September 21, 2014

September 21, 2014

Posted by **Byun** on Tuesday, December 20, 2011 at 12:45am.

- Math -
**Anonymous**, Tuesday, December 20, 2011 at 1:45amIf the initial term of an arithmetic progression is a1 and the common difference of successive members is d, then the nth term of the sequence is given by:

an = a1 + ( n - 1 ) * d

In this case:

a1 = 5

n = 5

a5 = 21

an = a1 + ( n - 1 ) * d

a5 = a1 + ( 5 - 1 ) * d

21 = 5 + 4 * d

21 - 5 = 4 d

16 = 4 d Divide both sides with 4

16 / 4 = 4 d / 4

4 = d

d = 4

a2 = a1 + d

a2 = 5 + 4

a2 = 9

- Math -
**drwls**, Tuesday, December 20, 2011 at 1:47amThe increase per term is (21 - 5)/(5 - 1)

= 16/4 = 4

Add 4 to the first term to get the second term

**Answer this Question**

**Related Questions**

Arithmetic Sequence - Given the third term of an arithmetic sequence less than ...

Math - The fifth term of an arithmetic progression is three times the second ...

Math - 3,5,-5... The first term in the sequence of #'s shown above is 3. Each ...

Math - A sequence is formed by adding together the corresponding terms of a ...

Maths - 1..The first 2 terms of a geometric progression are the same as the ...

Precalculus - The 8th term in an arithmetic sequence is 5, and the sum of the ...

math - find the rule for the Nth term of the arithmetic sequence. 11/2, 25/6, 17...

math - Find the 265th term of an arithmetic sequence whose second term is 5/8 ...

Math - Arithmetic Sequences - The sum of the 4th and the 14th term of an ...

Maths - The 3rd term of an AP is 10 more than the first term while the fifth ...