1. 11.1 Sequences & Summation Notation
Day Three
Revelation 3:20 "Here I am! I stand at the door and knock. If
anyone hears my voice and opens the door, I will come in and
eat with him, and he with me."
2. The sum of the ๏ฌrst n terms of a sequence is
called the nth partial sum and is denoted Sn
3. The sum of the ๏ฌrst n terms of a sequence is
called the nth partial sum and is denoted Sn
Find the indicated partial sums:
1) S10 for โ 3, โ 6, โ 9, โ 12, K
4. The sum of the ๏ฌrst n terms of a sequence is
called the nth partial sum and is denoted Sn
Find the indicated partial sums:
1) S10 for โ 3, โ 6, โ 9, โ 12, K
โ3 โ 6 โ 9 โ 12 โ 15 โ 18 โ 21โ 24 โ 27 โ 30
5. The sum of the ๏ฌrst n terms of a sequence is
called the nth partial sum and is denoted Sn
Find the indicated partial sums:
1) S10 for โ 3, โ 6, โ 9, โ 12, K
โ3 โ 6 โ 9 โ 12 โ 15 โ 18 โ 21โ 24 โ 27 โ 30
โ165
7. Find the indicated partial sums:
2) S6 for an = 10n โ 6
4 + 14 + 24 + 34 + 44 + 54
8. Find the indicated partial sums:
2) S6 for an = 10n โ 6
4 + 14 + 24 + 34 + 44 + 54
174
9. Find the indicated partial sums:
2) S6 for an = 10n โ 6
4 + 14 + 24 + 34 + 44 + 54
174
A partial sum can be done on your calculator
as the sum of a sequence. Try it ...
sum ( seq (10x โ 6, x, 1, 6, 1))
10. What is the syntax of this calculation?
sum ( seq (10x โ 6, x, 1, 6, 1))
11. What is the syntax of this calculation?
sum ( seq (10x โ 6, x, 1, 6, 1))
explicit formula
for the sequence
12. What is the syntax of this calculation?
sum ( seq (10x โ 6, x, 1, 6, 1))
explicit formula
for the sequence
summation
variable
13. What is the syntax of this calculation?
sum ( seq (10x โ 6, x, 1, 6, 1))
explicit formula
for the sequence
summation
variable
starts at
14. What is the syntax of this calculation?
sum ( seq (10x โ 6, x, 1, 6, 1))
explicit formula
for the sequence
summation
variable
starts at ends at
15. What is the syntax of this calculation?
sum ( seq (10x โ 6, x, 1, 6, 1))
explicit formula
for the sequence increases by
(called the step)
summation
variable
starts at ends at
19. Sigma Notation (or Summation Notation)
n
โa k = a1 + a2 + a3 +K + an
k=1
20. Sigma Notation (or Summation Notation)
n
โa k = a1 + a2 + a3 +K + an
k=1
is read
โthe sum of ak as k goes from 1 to n โ
21. Sigma Notation (or Summation Notation)
n
โa k = a1 + a2 + a3 +K + an
k=1
is read
โthe sum of ak as k goes from 1 to n โ
k is the summation variable ... or ...
index of summation
22. Sigma Notation (or Summation Notation)
n
โa k = a1 + a2 + a3 +K + an
k=1
is read
โthe sum of ak as k goes from 1 to n โ
k is the summation variable ... or ...
index of summation
This is the math shorthand for doing the
sum of a sequence
just like what we did on the calculator!
24. Example:
Express 2 + 5 + 8 + 11+ 14 + 17 + 20 + 23 + 26
using Sigma Notation
Find the explicit expression for this sequence.
That will be your ak .
Then, write the Sigma Notation!
25. Example:
Express 2 + 5 + 8 + 11+ 14 + 17 + 20 + 23 + 26
using Sigma Notation
Find the explicit expression for this sequence.
That will be your ak .
Then, write the Sigma Notation!
9
โ ( 3k โ 1)
k=1
26. Example:
Express 2 + 5 + 8 + 11+ 14 + 17 + 20 + 23 + 26
using Sigma Notation
Find the explicit expression for this sequence.
That will be your ak .
Then, write the Sigma Notation!
9
โ ( 3k โ 1)
k=1
Practice calculating this on your calculator.
27. Example:
Express 2 + 5 + 8 + 11+ 14 + 17 + 20 + 23 + 26
using Sigma Notation
Find the explicit expression for this sequence.
That will be your ak .
Then, write the Sigma Notation!
9
โ ( 3k โ 1)
k=1
Practice calculating this on your calculator.
sum ( seq ( 3x โ 1, x, 1, 9, 1)) 126
28. Find the sum by hand and verify with calculator:
8
1) โ ( 3k โ 4 )
k=1
29. Find the sum by hand and verify with calculator:
8
1) โ ( 3k โ 4 )
k=1
โ1+ 2 + 5 + 8 + 11+ 14 + 17 + 20
76
30. Find the sum by hand and verify with calculator:
8
1) โ ( 3k โ 4 )
k=1
โ1+ 2 + 5 + 8 + 11+ 14 + 17 + 20
76
sum ( seq ( 3x โ 4, x, 1, 8, 1))
31. Find the sum by hand and verify with calculator:
11
2) โ4
k=7
32. Find the sum by hand and verify with calculator:
11
2) โ4
k=7
4+4+4+4+4
20
33. Find the sum by hand and verify with calculator:
11
2) โ4
k=7
4+4+4+4+4
20
sum ( seq ( 4, x, 7, 11, 1))
or
sum ( seq ( 4, x, 1, 5, 1))
37. Properties of Sums
n n n
1. โ(a k + bk ) = โ ak + โ bk
k=1 k=1 k=1
38. Properties of Sums
n n n
1. โ(a k + bk ) = โ ak + โ bk
k=1 k=1 k=1
n n n
2. โ(a k โ bk ) = โ ak โ โ bk
k=1 k=1 k=1
39. Properties of Sums
n n n
1. โ(a k + bk ) = โ ak + โ bk
k=1 k=1 k=1
n n n
2. โ(a k โ bk ) = โ ak โ โ bk
k=1 k=1 k=1
n n
3. โ(c โ a ) = c โ โ a
k k
k=1 k=1
40. HW #3
โWe must not only give what we have, we must also
give what we are.โ Desire Joseph Cardinal Mercier