Without using a calculator, evaluate each of the following limits. Hint: What do the graphs of these functions look like?

1. $\lim\limits _ { x \rightarrow \infty } a ( x )$, where $a(x) = 10x^2$

2. $\lim\limits_{ x \rightarrow \infty } b ( x )$, where $b(x) = 0.5^x$

3. $\lim\limits_{ x \rightarrow \infty } c ( x )$, where $c(x) = 4\sqrt { x }$

4. $\lim\limits_{ x \rightarrow \infty } d ( x )$, where $d(x) = 5x − 3$