Find the sum of the first 12 terms of the sequences given in #1.
a.f(n) = 5*(2)^(n-1) ; for n = 1,2,3,4,…
b.a1 = 1/3 ; an+1 = = 3*an
a.
f(n)=5*2^(n-1)
f(1)=5*2^(1-1)=5*2^0=5
f(2)=5*2^(2-1)=5*2^1=10
f(3)=5*2^(3-1)=5*2^2=20
f(4)=5*2^(n-1)=5*2^3=40
...
b.
a1=1/3
a2=a1+1=3*a1=3*(1/3)=1
a3=a2+1=3*a2=3*1=3
...
get the idea?