fie F(x)=[tex]\frac{1}{1-x} - 1 si E(x)=[F(x):(1-\frac{1-2x^{2} }{1-x} )]x(4x^{2} -4x+1)
,unde x∈R/{0;\frac{1}{2}[/tex];1}.

a)calculati F(2)x F(-1)

b)aratati ca E(x)=2x-1