Question

Determine:
a) a soma dos 40 primeiros termos da P.A (3,7,11..)
b) a soma dos 50 primeiros termos da P.A (10,6...)
c) o primeiro termo de uma P.A em que a9=52 e S=252
d) o sétimo termo de uma P.A em que a¹=6 e S7=189

Answer 1

A) a soma dos 40 termos da pa=
(3,7,11,15,19,23,27,31,35,39,43,47,51,
55,59,63,67,71,75,79,83,87,91,95,99,
25
103,107,111,115,119,123,127,131,135,139,
143,147,151,155,159...)


B) a soma dos 50 primeiros termos da pa=
(10,6,2,-2,-6,-10,-14,-18,-22,-26,-30,-34,
-38,-42,-46,-50,-54,-58,-62,-66,-70,
-74,-78,-82,-86,-90,-94,-98,-102,-106,
-110,-114,-118,-122,-126,-130,-134,-138,
-142,-146,-150,-154,-158,-162,-166,-170,-174,-178,-182,-186,-189,-193...)

C)