## University Calculus: Early Transcendentals (3rd Edition)

$$\lim_{x\to7}\frac{4}{(x-7)^2}=\infty$$
$$A=\lim_{x\to7}\frac{4}{(x-7)^2}$$ As $x\to7$, $x-7$ approaches $0$ and $(x-7)^2$ approaches $0$ as well. Since $(x-7)^2\ge0$ for all $x$, $4/(x-7)^2$ will approach $\infty$. Therefore, $$A=\infty$$