a) E(-1/2)=[(-1/2)⁴+(-1/2)²+1]/[(-1/2+1)²-(-1/2)]=
=(1/16+1/4+1)/[(-1+2)/2]²+1/2=
=[(1+4+16)/16]/[(1/2)²+1/2]=
=(21/16)/(1/4+1/2)=(21/16)/(1+2)/4=(21/16)/(3/4)=21/16:3/4=
=21/16x4/3=simplif=7/4=1,75
b)(x+1)²>x
x²+2x+1>x
x²+2x-x+1>0
x²+x+1>0
c)E(x)=(x⁴+x²+1)/(x²+2x+1-x)=(x⁴+x²+1)/(x²+x+1)=
=(x²-x+1)(x²+x+1)/(x²+x+1)= se simplif=x²-x+1
d)E(n)=(n⁴+n²+1)/(n+1)²-n=(n²-n+1)(n²+n+1)/(n²+2n+1-n)=
=(n²-n+1)(n²+n+1)/(n²+n+1)=simplif=n²-n+1
daca n=0⇒E(n)=1
n=1⇒E(n)=1²-1+1=1
n=2⇒E(n)=2²-2+1=3
n-3⇒E(n)=3²-3+1=7
⇒n este un nr.impar
