# Formula Font Size in An Array or Equation?

    $$\left\{ \begin{array}{l} {\bar{\varphi }_{1} =\frac{d_{1} }{d_{1} +d_{n} } \varphi _{n} } \\ {\bar{\varphi }_{i} =\frac{d_{i} }{d_{i} +d_{i-1} } \varphi _{i-1} ,\qquad i=2,...,n-1} \\ {\bar{\varphi }_{n} =\frac{d_{n} }{d_{n} +d_{n-1} } \varphi _{n-1} } \end{array} \right.$$


The above Latex code shows the formula as follows:

It looks really ugle because letters in fractions are very small but the right part i=2,...,n-1 is large. Especially, n-1 looks just too long. Is there any way to beautify this or is is it the normal way of showing this formula?

Consider using dcases from mathtools:

\documentclass{article}

\usepackage{mathtools}

\begin{document}

$$\begin{dcases} \bar{\varphi}_1 = \frac{ d_1 }{ d_1 + d_n } \varphi_n \\ \bar{\varphi}_i = \frac{ d_i }{ d_i + d_{i-1} } \varphi_{i-1}, & i = 2,\dots,n-1 \\ \bar{\varphi}_n = \frac{ d_n }{ d_n + d_{n-1} } \varphi_{n-1} \end{dcases}$$

\end{document}


dcases places all the content within the construction is \displaystyle, resulting in the typical larger-format \frac display (similar to \dfrac from amsmath).

• Do you format your code directly or is there any good latex editor to beautify your coding? They look much clearer than my code. (not the display but the latex code itself). Aug 8, 2017 at 11:43
• @winston: I usually format it manually. However, you can process your code using something like latexindent. Also see Format the LaTeX code of an array.
– Werner
Aug 8, 2017 at 15:43

Below code helps you to improve the quality:

 $$\begin{cases} \bar{\varphi }_{1} &=\dfrac{d_{1} }{d_{1} +d_{n} } \varphi _{n} \\[6pt] \bar{\varphi }_{i} &=\dfrac{d_{i} }{d_{i} +d_{i-1} } \varphi _{i-1} ,\qquad i=2,...,n-1 \\[6pt] \bar{\varphi }_{n} &=\frac{d_{n} }{d_{n} +d_{n-1} } \varphi _{n-1} \end{cases}$$