\(\lim\limits_{x\rightarrow+\infty}=\dfrac{x^4+7}{x^4+1}\)
\(=\lim\limits_{x\rightarrow+\infty}\dfrac{x^4\left(1+\dfrac{7}{x^4}\right)}{x^4\left(1+\dfrac{1}{x^4}\right)}\)
\(=1\)
\(lim\left(x->+vc\right)\dfrac{x^4+7}{x^4+1}=lim\left(x->+vc\right)\dfrac{1+\dfrac{7}{x^4}}{1+\dfrac{1}{x^4}}=\dfrac{1}{1}=1\)