E4. Dau coroana pt cel mai bun raspuns
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Explicație pas cu pas:
f(x)=y
(1-x)/(1+x)=y
1-x=y+yx
yx+x=1-y
x(1+y)=1-y
x=(1-y)/(1+y)
f^-1(x)=(1-x)/(1+x)
f^-1 (x) :R-{-1}-->R-{-1}
Bafta!