Arithmetic Sequences nth term

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Arithmetic Sequences nth term

• The 4 term sequence 2, 9, 16, 23
• Starts with 2, then adds the common difference of
  7, 3 more times
• The 7 term sequence 2, 6, 10, 14, 18, 22, 26
• Starts with 2, then adds the common difference of
  4, 6 more times

t1
d
(n-1)
tn
tn t1 d(n-1) The nth term of an arithmetic
sequence
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Finding tn (Arithmetic)

• Find tn for the following arithmetic sequences
• 1. 5, 8, 11, 14, 2. 7, 11, 15, 19,

tn t1 d(n-1)
tn t1 d(n-1)
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Using tn

• After finding tn, you can then find any term in
  the sequence specifically.
• Find t70 for the following arithmetic sequence
• 3. 357, 346, 335,

1. Find tn 2. Plug in 70 for n and simplify.
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Using tn

• You can also find specific terms in a sequence
  given any 2 terms of the sequence by using the
  formula for tn.
• Find t20 for the arithmetic sequence where t2
  13 and t5 22.

• Use the tn formula to set up an equation using t2
  or t5.
• Determine d by looking at number of differences
  between the given terms.
• Plug in d into the equation from 1 to find t1