1686351
Description
Mind Map by Edward Corke, updated more than 1 year ago
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Created by Edward Corke
about 10 years ago
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Maths-Algebra: Sequences (nth Term)
- Finding the nth Term
- nth: 1 2 3 4
- term: 5 8 11 14
- Formula:
- nth term = dn + (a - d)
- d is the common
difference and a is
the first term
- d is the common
difference and a is
the first term
- nth term = dn + (a - d)
- --> +3 -->
- The difference
between the numers
is 3, so 3n is the
formula.
- 3n: 3 6 9 12
- +2
- You have +2
to get to the
term
- You have +2
to get to the
term
- Term: 5 8 11 14
- +2
- So the
expression for
the nth term is
3n + 2
- 3n: 3 6 9 12
- The difference
between the numers
is 3, so 3n is the
formula.
- nth: 1 2 3 4
- Deciding if a Term is in a Sequence
- It's dead easy!
- Example:
- The nth term of a sequence is given by n^2 - 2.
- Find the 6th term in the sequence.
- put n=6 into the expression:
- 6^2 - 2 = 36 - 2
- = 34
- = 34
- 6^2 - 2 = 36 - 2
- put n=6 into the expression:
- Is 45 a term in the sequence?
- Set it equal to 45... n^2 - 2 = 45
- n^2 = 47
- n = √47 = 6.8556...
- n is not a whole
number, so 47 is not
in the sequence:
n^2 - 2
- n is not a whole
number, so 47 is not
in the sequence:
n^2 - 2
- n = √47 = 6.8556...
- n^2 = 47
- Set it equal to 45... n^2 - 2 = 45
- Find the 6th term in the sequence.
- The nth term of a sequence is given by n^2 - 2.
- Example:
- It's dead easy!
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