1. 0 + 1 - 2 + 3 - 4...100=___ 2. 0 + 1 + 2 + 3 + 4 +...+ 98 + 99 + 100=_____ state solution and explanation of how you got to the solution, thanks!
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Originally Posted by Alana0001 1. 0 + 1 - 2 + 3 - 4...100=___ 2. 0 + 1 + 2 + 3 + 4 +...+ 98 + 99 + 100=_____ state solution and explanation of how you got to the solution, thanks! In both cases you're expected to know and use the formula for the sum of an arithmetic series. Note that the first one can be re-arranged as (1 + 3 + 5 + .... + 99) - (2 + 4 + 6 + ...... + 100).
Originally Posted by Alana0001 1. 0 + 1 - 2 + 3 - 4...100=___ 2. 0 + 1 + 2 + 3 + 4 +...+ 98 + 99 + 100=_____ state solution and explanation of how you got to the solution, thanks! Use these formulas: $\displaystyle 1+2+3+...+n=\frac{n(n+1)}{2} $ $\displaystyle 1+3+5+...+n=\left(\frac{n+1}{2}\right)^2$
Last edited by ely_en; Sep 2nd 2008 at 11:00 PM.
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