TeX Quellcode:

\begin{array}{rcl} \sum\limits_{i=0}^4 (-1)^{i+1}(i-2)x &=& (-1)^{0+1}(0-2)x+(-1)^{1+1}(1-2)x+(-1)^{2+1}(2-2)x+(-1)^{3+1}(3-2)x+(-1)^{4+1}(4-2)x \cr &=& (-1)^1 \cdot (-2)x+(-1)^2 \cdot (-1)x+(-1)^3 \cdot 0x+(-1)^4 \cdot 1x+(-1)^5 \cdot 2x \cr &=& -1 \cdot (-2)x+1 \cdot (-1)x+0+1 \cdot 1x+(-1) \cdot 2x \cr &=& 2x-1x+1x-2x \cr &=& 0 \end{array}