Question

Determine a fórmula do termo geral de cada p.g
a) (2,8,...)
b) (3,9,...)
c) (2,1,...)

Answer 1

Vejamos: a) PA (2,8,...) A1 = 2 r = 6 An = A1 + (n - 1) . r An = 2 + (n - 1) . 6 An = 2 + 6n - 6 An = 6n - 4 b) PA (3,9,...) A1 = 3 r = 6 An = A1 + (n - 1) . r An = 3 + (n - 1) . 6 An = 3 + 6n - 6 An = 6n - 3 c) PA (2,1,...) A1 = 2 r = -1 An = A1 + (n - 1) . r An = 2 + (n - 1) . (-1) An = 2 - n + 1 An = -n + 3