Text Formatting ⇒ enumitem | Vertical Alignment in List

[ghostanime2001]

How can I have the "y" in "y(x,t)" align vertically with a), b) and the "k" in "k=2pi/lambda" ? But keeping the indent between the letters and [blah blah] in

a) [blah blah] and b) [blah blah] the same?

Code: Select all

\documentclass[fleqn]{article}
\usepackage{fullpage}
\usepackage[inline]{enumitem}
\usepackage[margin=1in]{geometry}
\usepackage{graphicx}
\usepackage{mathtools}
\usepackage{amsmath}
\usepackage{siunitx}
\pagestyle{empty}
\setlength{\mathindent}{0in}
\renewcommand{\labelenumi}{\arabic{enumi}.}
\renewcommand{\labelenumii}{\alph{enumii})}
\begin{document}
\begin{enumerate}[nolistsep,leftmargin=0cm]
\item
$\begin{aligned}[t]
y(x,t)=0.015\sin(25-1200t)
\end{aligned}$
\begin{enumerate}[nolistsep]
\item
$\begin{aligned}[t]
y(x,t)=0.015\sin(25-1200t)
\end{aligned}$
\item
$\begin{aligned}[t]
v=\lambda f
\end{aligned}$
\hspace{1.4in}
\smash{$\begin{aligned}[t]
&v=(0.25)(191) \\
&v=47.75 
\end{aligned}$}
\begin{align*}
\begin{aligned}[t]
&k=\dfrac{2\pi}{\lambda} \\
&\lambda k=2\pi \\
&\lambda=\dfrac{2\pi}{k} \\
&\lambda=\dfrac{2\pi}{25} \\
&\lambda=0.25
\end{aligned}
\hspace{1cm}
\begin{aligned}[t]
&\omega=2\pi f  \\
&\dfrac{\omega}{2\pi}=f \\
&\dfrac{1200}{2\pi}=f \\
&191=f 
\end{aligned}
\end{align*}
\end{enumerate}
\end{enumerate}
\end{document}