大括号显示

\left\{  
             \begin{array}{**lr**}  
             x=\dfrac{3\pi}{2}(1+2t)\cos(\dfrac{3\pi}{2}(1+2t)), &  \\  
             y=s, & 0\leq s\leq L,|t|\leq1.\\  
             z=\dfrac{3\pi}{2}(1+2t)\sin(\dfrac{3\pi}{2}(1+2t)), &    
             \end{array}  
\right.

对比括号

\left\{  
\begin{array}{**rcl**}
    IF_{k}(\hat{t}_{k,m})=IF_{m}(\hat{t}_{k,m}), & \\
    IF_{k}(\hat{t}_{k,m}) \pm h= IF_{m}(\hat{t}_{k,m}) \pm h  , &\\
    \left |IF'_{k}(\hat{t}_{k,m} - IF'_{m}(\hat{t}_{k,m} \right |\geq d , &   
\end{array}
\right.  
f(x)=\left\{
\begin{aligned}
&(x^2+y^2)cos\frac{1}{\sqrt{x^2+y^2}}\ ,& \ (x^2+y^2)\ne 0 \\
&0\ ,&\ (x^2+y^2)= 0
\end{aligned}
\right.

备注：
可以使用\big, \Big, \bigg, \Bigg控制括号的大小

\Bigg ( \bigg [ \Big { \big \langle \left | | \frac{a}{b} | \right | \big \rangle \Big } \bigg ] \Bigg )

空行

\Large
e^x=1+x+\frac{x^2}{2!}+\frac{x^3}{3!}+\frac{x^4}{4!}+\dots+\frac{x^n}{n!}+o(x^n)\\
 ~\\
\Large
sinx=x-\frac{x^3}{3!}+\dots+\frac{(-1)^{n}}{(2n+1)!}x^{2n+1}+o(x^{2n+1})\\
~\\
\\
\Large
cosx=1-\frac{x^2}{2!}+\dots+\frac{(-1)^{n}}{2n!}x^{2n}+o(x^{2n})\\
~\\
\Large
\frac{1}{1-x}=1+x+x^2+x^3+\dots+x^n+o(x^n)\\
~\\
\Large
\frac{1}{1+x}=1-x+x^2-x^3+\dots+(-1)^nx^n+o(x^n)\\
~\\
\Large
ln(1+x)=x-\frac{x^2}{2}+\frac{x^3}{3}-\frac{x^4}{4}+\dots+\frac{(-1)^{n-1}x^n}{n}+o(x^n)\\

调节字体大小

\tiny
\scriptsize
\footnotesize
\small
\normalsize
\large
\Large
\LARGE
\huge
\Huge