lim【x→∞】[(x^2+1)/(x+1)-(ax+b)]
=lim【x→∞】[(x²+1)-(ax+b)(x+1)]/(x+1)
=lim【x→∞】[(1-a)x²-(a+b)x+1-b]/(x+1)
=5
得 1-a=0
-(a+b)=5
解得a=1
b=-6
lim【x→∞】[(x^2+1)/(x+1)-(ax+b)]
=lim【x→∞】[(x²+1)-(ax+b)(x+1)]/(x+1)
=lim【x→∞】[(1-a)x²-(a+b)x+1-b]/(x+1)
=5
得 1-a=0
-(a+b)=5
解得a=1
b=-6