Tagging math alignments: cases list

1 On negative values

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\[ f(x)= \begin {cases*} -1 & if $x<0$, see section \href{#Sect.1}{1}\\ 1 & if $x \geq 0$.\end {cases*} \]

y(x)=\begin{cases*}-1&if $x<0$, see section \href{\#Sect.1}{1}\\ 1&if $x\geq 0$.\end{cases*}

g(x)=\begin{cases*}-1&if $x<0$, see section \href{\#Sect.1}{1}\\ 1&if $x\geq 0$.\end{cases*}

h(x)=\begin{cases*}-1&if $x<0$, see section \href{\#Sect.1}{1}\\ 1&if $x\geq 0$.\end{cases*}

k(x)=\begin{cases*}-1&if $x<0$, see section \href{\#Sect.1}{1}\\ 1&if $x\geq 0$.\end{cases*}

f(x)=\begin{cases*}-1&if $x<0$, see section \href{\#Sect.1}{1}\\ 1&if $x\geq 0$.\end{cases*}