a) 0 ° 1 = (0+1+1)/ ( 0²+1²+1) = 2/ 2 = 1
b) x° x = (x+x+1) / (x²+x²+1) = (2x+1)/ (2x²+1)
Dar x°x = 1 => (2x+1)/ (2x²+1) = 1
2x+1 = 2x²+1
2x²-2x+1-1= 0
2x²-2x= 0
2x(x-1)=0
2x=0 => x1 = 0
x-1=0 => x2 = 1
c) x° (-x) </ 1
x°(-x) = (x-x+1)/ (x²+(-x)² +1) = 1/(2x²+1)
notam x = -1 => 1/(2*1+1) =1/3 </ 1
notam x = 0 => 1/(0+1) = 1/1 = 1 </1
notam x= 4 => 1/(2*16+1) = 1/33 </ 1
=> oricare ar fi x apartine R, x ° (-x) </ 1