Question

ajutor la matematica. . . dau coroana urgent daca raspundeti in max 10min​

Answer 1

   

$\displaystyle\bf\\z=(-1)^1+(-1)^3+(-1)^5+...+(-1)^{2011}\\\\Calculam~numarul~de~termeni~n.\\\\n=\frac{2011-1}{2}+1=\frac{2010}{2}+1=1005+1=\boxed{\bf1006~termeni}$

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$\displaystyle\bf\\Fiecare~din~cei~1006~termeni~este~format~din:\\\\(-1)~ridicat~la~o~putere~numar~impar.\\\\(-1)^{numar~impar}=-1\\\\z=(-1)^1+(-1)^3+(-1)^5+...+(-1)^{2011}=\\\\=\underbrace{(-1)+(-1)+(-1)+...+(-1)}_{1006~termeni}=\\\\=(-1)\times1006=-1006\\\\\boxed{\bf z=-1006}$