how do you find the indicated term of a sequence that is both Arithmetic and geometric? for example: 1,3,7,15,31,63
if i remember correctly there is not one
see if i can remember the proof
u find a relationship between the sequence but it cannot be arithmetic or geometric
but it can be a combination
your sequence above is \[2^n-1\]for \[n=1,2,3,...\]
can i have my dirty martini now?
^correct
uh not the martini lol
actually trying to find the n th term
i wrote the nth term. it is \[2^n-1\] the "nth term" naturally has an "n" in it yes?
first term is \[2^1-1=1\] second term is \[2^2-1=3\]third term is \[2^3-1=7\] nth term is \[2^n-1\]
got it yes?
the problem reads 1,3,7,15,31,63....,a11
ahh you want the eleventh term maybe
that would be \[2^{11}-1\]
yes want the 11th term
which is \[2^{11}-1=2047\]
(calculator)
using the same problem what if I wanted to find the 5th term
nevermind, i got it. can I give you 1 more problem
sure name it
a,6,c,12,e,18 ...., a25
there must be some sort of instructions yes? is it geometric?
instructions read find the term, yes geometric
because it looks like it should be \[3,6,9,12, 15,18,...\]
and that is not geometric, it is arithmetic. you are adding 3 to one term to get the next
ok, do the 25th term will be a letter, right? how do i determine the lettter
so the formal would be \[a_n=3n\] and therefore \[a_{25}=75\]
*formula
why is the answer a number and not a letter ]
oh i thought the letters represented numbers you were not given. maybe i am wrong
if so i guess it is the 25th letter of the alphabet, which is y
no I think you are right. the letters are numbers not given
thank you, just figured out y as well
well i am no sure, but it is either y or 75
what kind of math is this?
honors geometry
just transferd into the class and missed the first 2 lessons
what if the ratio is not constant, example: 1,3,6,10,15,21... a30
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