[tex]\bf \textit{difference of squares}
\\ \quad \\
(a-b)(a+b) = a^2-b^2\qquad \qquad
a^2-b^2 = (a-b)(a+b)\\\\
-------------------------------\\\\
v^4-1\implies v^4-1^4\implies (v^2)^2-(1^2)^2\implies \underline{(v^2-1^2)}(v^2+1^2)
\\\\\\
\underline{(v-1)(v+1)}(v^2+1^2)[/tex]
