Question

determine o a18 da p.a (-3,-1,1,3,...)

Answer 1

a1 = - 3          r = - 1 - (- 3)              a18 = ?
                       r = - 1 + 3
                       r = 2

a18 = a1 + 17 r
a18 = - 3 + 17.2
a18 = - 3 + 34
a18 = 31


P.A( -3, -1, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31 )