Find the first five terms of the sequence defined below, where n represents the position of a term in the sequence. Start with n = 1.

an = 10n2 − 7n + 10

1 answer

To find the first five terms of the sequence defined by the formula \( a_n = 10n^2 - 7n + 10 \), we will calculate the value of \( a_n \) for \( n = 1, 2, 3, 4, \) and \( 5 \).

  1. For \( n = 1 \): \[ a_1 = 10(1^2) - 7(1) + 10 = 10(1) - 7 + 10 = 10 - 7 + 10 = 13 \]

  2. For \( n = 2 \): \[ a_2 = 10(2^2) - 7(2) + 10 = 10(4) - 14 + 10 = 40 - 14 + 10 = 36 \]

  3. For \( n = 3 \): \[ a_3 = 10(3^2) - 7(3) + 10 = 10(9) - 21 + 10 = 90 - 21 + 10 = 79 \]

  4. For \( n = 4 \): \[ a_4 = 10(4^2) - 7(4) + 10 = 10(16) - 28 + 10 = 160 - 28 + 10 = 142 \]

  5. For \( n = 5 \): \[ a_5 = 10(5^2) - 7(5) + 10 = 10(25) - 35 + 10 = 250 - 35 + 10 = 225 \]

Now we can summarize the first five terms of the sequence:

  • \( a_1 = 13 \)
  • \( a_2 = 36 \)
  • \( a_3 = 79 \)
  • \( a_4 = 142 \)
  • \( a_5 = 225 \)

Thus, the first five terms of the sequence are: 13, 36, 79, 142, 225.