+a. daca x + 1 ≠ 0 ; x ≠ - 1
nu este definita pentru x = -1
x∈ R \ { - 1 }
b. F(x)= [ 2· ( x + 1) + 1·( x² - x + 1) - 2x - 2] / ( x+ 1)·( x² - x + 1) =
= [ 2x + 2 +x² - x + 1 - 2x - 2 ] / ( x +1)·( x² - x + 1)
= ( x² - x + 1) / ( x +1) · ( x² - x + 1) = 1 / ( x +1)
G(x) = ( x + 1) ·F(x) = 1 = 1² patrat perfect
c. F(1)·F(2) + F(2)·F(3) + ..... + F(2015)·F(2016) =
= 1 / 2 · 3 + 1 / 3 · 4 + .......... + 1 /2016 ·2017 =
↓ ↓ ↓
= 1 /2 - 1 /3 + 1 /3 - 1 /4 + ..... + 1 /2016 - 1 /2017
= 1 /2 +0 + 0 + ............. - 1 /2017
= ( 2017 -2) / 2·2017 = 2015 / 4034
