牛顿微分符号一阶微分\dot{[变量]}\bbox[#ACF,20px,border:1px]{\quad\dot y+py=q\quad}\\二阶微分\ddot{[变量]}\bbox[#CAF,20px,border:1px]{x^2\ddot y+2x\dot y+\Big[x^2-n(n+1)\Big]y=0}\\到了三阶微分以上,牛顿微分符号便显得相形见拙了,幸有更恰当的替代方案\bbox[#FAA,...
⌟\lrcorner┘ ⌜\ulcorner┌ ⌝\urcorner┐ $\$$ £\pounds£ ¥\yen¥ √\surd√ °\degree° ℧\mho℧ ╲\diagdown╲ ╱\diagup╱ ♭\flat♭ ♮\natural♮ ♯\sharp♯ ♡\heartsuit♡ f\tiny{\operatorname{f}}f arg\tiny{\arg}arg dim\tiny{\dim}dim...