# 蜗牛线

a = 的蜗牛线

${\displaystyle r={\frac {a\sin \theta }{\theta }}}$

${\displaystyle (x^{2}+y^{2})\arctan {\frac {y}{x}}=ay}$

${\displaystyle x={\frac {a\sin t\cos t}{t}}}$
${\displaystyle y={\frac {a\sin ^{2}t}{t}}}$