Question

Dado a Pa (2.....23) Interpole 7 termos e faça a soma.

Answer 1

a1=2
a9=23
a9=a1+(9-1).r
23=2+8.r
23-2=8r
8r=21
r=21/8
a2=2+21/8=16/8+21/8=37/8
a3=37/8+21/8=58/8=29/4
a4=58/8+21/8=79/8
a5=79/8+21/8=100/8=25/2
a6=100/8+21/8=121/8
a7=121/8+21/8=142/8=71/8
a8=142/8+21/8=163/8

S9= (2+23).9/2
S9=25.9/2
S9=225/2
S9=112,5