In Arithmetic sequence
a13=4;a21=8;a5=?
What will be the answer?? help
Lets assume this question is: We have an arithmetic progression , and and . What isOriginally Posted by machilove
Given that is an arithmetic progression we know that , where is the first term, and
is the common difference.
So:
and:
Subtracting the first of these from the second gives:
, so .
Substituting this value for back into one of the equations gives .
So:
RonL