Algebra2 Selection of Terms in an A.P.

To enroll in any of our courses, click here

Selection of Terms in an A.P.
Sometimes we require certain number of terms in A.P. The following ways of selecting terms are generally very convenient.

Number of Terms	Terms	Common Difference
3	a-d, a, a+d	d
4	a-3d, a-d, a+d, a+3d	2d
5	a-2d, a-d, a, a+d, a+2d	d
6	a - 5d, a - 3d, a - d, a + d, a + 3d, a + 5d	2d

It should be noted that in case of an odd number of terms, the middle term is a and the common difference is d while in case of an even number of terms the middle terms are a -d,a + d and the common differences is 2d.

People who saw this lesson also found the
following lessons useful:

Common Tangents of Two Circles

Solving a System of Equations

Angles In Alternate Segments

Problems on Age

Pythagoras Theorem

Example: The sum of three numbers in A.P is -6, and their product is 24. Find the numbers.
Solution: Let the numbers be (a - d), a, (a+d). Then,
Sum = -6

(a-d) + a + (a+d) = -6

3a = -6

a = -2
Product = 24

(a - d) (a) (a + d) = 24

a(a²-d²) = 24

(-2)(4 - d² ) = 24 ...[a = -2]

d² = 16 =

4
If d = 4, the numbers are - 6, - 2, 2. If d = - 4, the numbers are 2, - 2, - 6.
Thus, the numbers are -6,-2, 2, or 2, - 2, -6.


	As many of you know, Winpossible's online courses use a unique teaching method where an instructor explains the concepts in any given area to you in his/her own voice and handwriting, just like you see your teacher explain things to you on a blackboard in your classroom. All our courses include teacher's instruction, practice questions as well as end-of-lesson quizzes for practice. You can enroll in any of our online courses by clicking here. The format of Winpossible's online courses is also very suitable for teachers who are using an interactive whiteboard such as Smartboard on Promethean in their classrooms, because the course lessons can be easily displayed on such interactive whiteboards. Volume pricing is available for schools interested in our online courses. For more information, please contact us at educators@winpossible.com.