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Calculati:
a) (-1) la puterea n +(-1) la puterea n+1 , n aparține lui N
b) (-1) la puterea 2 + (-1) la puterea 2n+1
c) [(-1) la puterea n × (-2) la puterea 2n-4 la puterea n] ÷ (-4) la puterea n


Răspuns :

a) (-1)^n+(-1)^(n+1)=
(-1)^n+(-1)^n·(-1)=
(-1)^n(1-1)=(-1)^n·0=0

b) (-1)²+(-1)^(2n+1)=
1+(-1)^2n·(-1)=
1-1=0

c)[(-1)^n·(-2)^2n-4^n]:(-4)^n=
[(-1)^n·(-4)^n-4^n]:(-4)^n=
[4^n-4^n]:(-4)^n=0