Question

Calcule a soma dos 6 primeiros termos da PG.. somente A e B

Answer 1

a
a1 = 1/4
a2 = 1/2
a3 = 1
q = 1/2:1/4 =  1/2 * 4/1 = 4/2 = 2 ***
n = 6
S6 =  1/4 ( 2⁶  - 1)/ ( 2 - 1)
S6 = 1/4( 64 - 1)/1
S6 = 1/4 ( 63/1)  = 63/4 ****

b

a1 = 1
a2 = 1/3
q = 1/3 : 1/1 = 1/3 * 1/1  = 1/3 ***
n = 6

S6 = 1 [ ( 1/3)⁶  - 1)/ ( 1/3 - 1/1)
S6 = ( 1/729 - 1/1)/ ( -2/3)
S6 = ( - 728/729 ) / ( - 2/3)
S6 = (-728/729)  * ( - 3/2 )
S6 = 2184/1458  =1092/729 = 364/243 ***