Question

Write an equation for the nth term of the arithmetic sequence −4, 1, 6, 11, .... Then find a50.

Answer 1

Hello !!

For you answer this question, you only need make use of this method below. See the resolution.

The common difference.

d = (An - Ak)/(n - k)

d = (1 - (-4))/(2 - 1)

d = (1 + 4)/1

d = 5/1

d = 5

The nth term.

An = Ak + (n - k) × d

An = -4 + (n - 1) × 5

An = -4 + 5n - 5

An = 5n - 5 - 4

An = 5n - 9

The 50th term.

An = Ak + (n - k) × d

A50 = -4 + (50 - 1) × 5

A50 = -4 + 49 × 5

A50 = -4 + 245

A50 = 241

Final result :

nth term is An = 5n - 9.

50th term is 241.

I hope I have collaborated !