Question

A1=8 and a2 =21 Determine the common difference then write the explicit formula of the equation

Answer 1

• 
  `a_n = 8 + 13(n - 1)`

Given :

• 
  `a_1 = 8`
• 
  `a_2 = 21`

Task :

• To determine the common difference and write the explicit formula of the equation.

Solution :

Firstly,

we'll find the common difference

• 
  `= a_2 - a_1 \\ = 21 - 8 \: \\ = 13 \: \: \: \: \: \: \: \: \: \:`

Thus, the common difference is 13.

We know that,

• 
  `Explicit \: formula : \\ a_n = a_1 + r(n-1)`

Where,

• n = nth term
• a1 = first term
• r = common difference

Plugging in the values according to the equation, we get our required explicit formula:

• 
  `a_n = 8 + 13(n - 1)`