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测试公式显示

$e^{i\theta }=\cos (\theta )+i\sin (\theta )$

$|x-y{|}^2+|y-z{|}^2\ge |x-z{|}^2$

$1+x+\frac{x^2}{2}-\frac{x^4}{8}-\frac{x^5}{15}-\frac{x^6}{240}+\frac{x^7}{90}+\frac{31x^8}{5760}+\frac{x^9}{5670}-\frac{2951x^{10}}{3628800}+O\left(x^{11}\right)$

$(1+y+\frac{y^2}{2}+\frac{y^3}{6}+O\left(y^4\right))+x(1+y+\frac{y^2}{2}+\frac{y^3}{6}+O\left(y^4\right))+x^2(\frac{1}{2}+\frac{y}{2}+\frac{y^2}{4}+\frac{y^3}{12}+O\left(y^4\right))+x^3(\frac{1}{6}+\frac{y}{6}+\frac{y^2}{12}+\frac{y^3}{36}+O\left(y^4\right))+O\left(x^4\right)$