1.2 ARITHMETIC SEQUENCE

• Arithmetic Sequence - This is a sequence where you can add a constant(d) to a term to find the other term next to it.
• Common Difference - This is what the constant(d) is called.
• if the common difference is 5, and the first term is 3, what is a₃?

  13
• Find the common difference presented in the picture

  d = 5

  
• Find the common difference in the picture.

  d = -7

  
• Find the common difference

  Find the next term(a₅)

  d = -5

  a₅ = -19

  
• Find the common difference

  Find the next term(a₅)

  d = 12

  a₅ = 59

  
• Find the common difference

  Find the next term(a₅)

  d = -2x

  a₅ = (-5x - 8)

  
• Find the common difference

  Find the next term(a₅)

  d = 2s + 1

  a₅ = 9s

  
• What is the formula in finding any term in an arithmetic sequence?

  (Note: Write subscript like aₙ as [an]. For example, a₅ we write it as a5.)

  an = a1 + (n-1)d
• Name the parts of the formula.

  (Note: Write subscript like aₙ as [an]. For example, a₅ we write it as a5.)

  • First term in the sequence = a1
  • Last term in the sequence = an
  • The number of terms in the sequence = n
  • Common Difference = d
• Find the 14th term in the sequence using the formula.

  a₁₄ = 43

  
• Find the 14th term of the sequence IF the first term is 5

  IF the first term is 5

  IF the common difference is -6

  A₁₄ = -73
• Substitute the following terms in a formula.

  Last term = 20

  First term = 5

  Common Denominator = 5

  Number of terms = 4

  (Note: Write subscript like aₙ as [an]. For example, a₅ we write it as a5.)


  a20 = 5 + (4-1)5