Answer
a. $1/2$
b. see graph and explanations.
Work Step by Step
a. Since $\lim\limits_{x\to 0}(\frac{1}{2}-\frac{x^2}{24})=\frac{1}{2}$, using the Sandwich Theorem of limits, we have:
$\lim\limits_{x\to 0}\frac{1-cos(x)}{x^2}=\frac{1}{2}$
b. The three functions are shown in the graph. It can be seen that as x gets close to zero, all functions meet at $1/2$.
