+577 I don't understand how to find a sigma equation from a set of numbers.
-5+2+9+16+...+261+268
How do I get a sigma equation from this?
+118670
My answer is the same as EP's
EP you might like to look at my Latex here too :)
-5+2+9+16+...+261+268
This is the sum of an AP
a=-5, d=7,
\(T_n=a+(n-1)d\\ T_n=-5+(n-1)*7\\ T_n=-5+7n-7\\ T_n=7n-12\\ Find\;n\;when\;T_n=268\\ 268=7n-12\\ 280=7n\\ n=40 \)
\(\displaystyle\sum_{n=1}^{40}\;7n-12 \\\)
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LATEX COMMAND
\displaystyle\sum_{n=1}^{40}\;7n-12
