- #1
chwala
Gold Member
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- Homework Statement
- Find the nth term of the sequence ##[2, 9 , 28, 65, 126]##
- Relevant Equations
- sequences
My working...i need to arrange this in an array,
##[2, 9, 28, 65, 126]##
##[ 7, 19, 37, 61 ]##
##[ 12, 18, 24 ]##
##[ 6, 6 ]##
I was able to solve this by coming up with 4 simultaneous equations,
third difference we have a constant implying a cubic sequence... therefore our sequence will be of the form ##U_n= an^3 +bn^2+cn+d##
I managed to solve it...allow me to post the 4 simultaneous equations later...i finish with class...to eventually realize ##U_n= n^3 +1##
I am seeking an alternative method...cheers
##[2, 9, 28, 65, 126]##
##[ 7, 19, 37, 61 ]##
##[ 12, 18, 24 ]##
##[ 6, 6 ]##
I was able to solve this by coming up with 4 simultaneous equations,
third difference we have a constant implying a cubic sequence... therefore our sequence will be of the form ##U_n= an^3 +bn^2+cn+d##
I managed to solve it...allow me to post the 4 simultaneous equations later...i finish with class...to eventually realize ##U_n= n^3 +1##
I am seeking an alternative method...cheers
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