Question

Evaluate the summation of 2n+5 from n=1 to 12

29
36
216
432

Answer 1

`\bf \sum\limits_(n=1)^(12)\ 2n+5\implies \sum\limits_(n=1)^(12)\ 2n+\sum\limits_(n=1)^(12)\ 5\implies 2\sum\limits_(n=1)^(12)\ n+\sum\limits_(n=1)^(12)\ 5 \\\\\\ 2\cdot \cfrac{12(12+1)}{2}+(12\cdot 5)\implies 156+60\implies 216`