How do I compute $\text{Pr}(|U|<\text{const})$ in Matlab?

Question

I'm trying to type a command into Matlab which would for $U\sim N(0,1)$ and $p_1=\text{Pr}(|U|<\frac{1}{5}\sqrt{21})$ obtain $p_1\doteq 0.64$.

I have exhausted all possibilities but nothing works. Please see the two pages from a book I'm studying.

Answer 1

Since it’s standard normal you just find the function that gives cdf of normal $\Phi$ and do this:

$$P(|U|\leq a) = 1-2\Phi(-a)$$