c. 1/3 + 2/3 + 1 +....
sn=n/2(2a+(n-1)b)
s18 = 18/2(2.1/3 + (18-1).1/3)
s18 = 9(2/3 + 17/3)
s18 = 9(19/3) = 57
" Life is not a problem to be solved but a reality to be experienced! "
© Copyright 2013 - 2025 KUDO.TIPS - All rights reserved.
Awalnya 1/3, bedanya 1/3
S18 = 9 (2/3 + 17/3)
9(19/3) = 57
D.
Awalnya 2/3, bedanya 1/2
S15 = 15/2 (4/3 + 14/2)
15/2(4/3 + 21/3)
15/2 (25/3)
625/10 = 125/2
c. 1/3 + 2/3 + 1 +....
sn=n/2(2a+(n-1)b)
s18 = 18/2(2.1/3 + (18-1).1/3)
s18 = 9(2/3 + 17/3)
s18 = 9(19/3) = 57