rumus suku ke-ndari barisan 4,8,16,32,64adalah

[tex]u1 = {2}^{n + 1} = 2 {}^{1 + 1} = 2 ^{2} = 4[/tex]
[tex]u2 \: = 4 = {2}^{n + 1} = 2 {}^{2 + 1} = 2 ^{3} = 8[/tex]

[tex]u3 = {2}^{n + 1} = 2 {}^{3 + 1} = 2 ^{4} = 16[/tex]
[tex]u4 \: = {2}^{n + 1} = 2 {}^{4 + 1} = 2 ^{5} = 32[/tex]
jadi rumus suku ke -n adalah
[tex] = {2}^{ n+ 1} [/tex]

un:a+(n-1)b
:4+(n-1)4
:4+4n-4
:4-4+4n
4n-1