Posted by Elisabeth on .
Find the sum of the first 12 terms of the sequences given in #1.
a.f(n) = 5*(2)^(n1) ; for n = 1,2,3,4,…
b.a1 = 1/3 ; an+1 = = 3*an

Math 
MathMate,
a.
f(n)=5*2^(n1)
f(1)=5*2^(11)=5*2^0=5
f(2)=5*2^(21)=5*2^1=10
f(3)=5*2^(31)=5*2^2=20
f(4)=5*2^(n1)=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?