What's wrong with this?

\partial{Q}=\frac{1}{2}\frac{\sum{h_f}}{\sum \left({\frac{h_{fi}}{Q_i}\right)}}

I keep getting errors.

  • 2
    (1) Welcome, (2) Next time please provide a full minimal example, that others can just copy and use. (3) Please cite the error you get
    – daleif
    Commented Jul 20, 2016 at 15:36
  • It should be }\right) instead of\right)} (in my opinion, the corresponding pair of braces isn't necessary).
    – Bernard
    Commented Jul 20, 2016 at 16:13

1 Answer 1


Make sure that you have put the curlybraces at the correct position. Also, the pair causing problems here, doesn't do anything here, so I suggest just removing it.

When there are lots of groups like {} and such, It gets difficult to see the where each group begins and ends. Try to add some space between, to ease the reading. Spaces are ignored in math-mode, so you can use as much as you want.

I have added two suggestions on how you could make it easier to read. The first simply adds some single-spaces here and there, while the other one adds linebreaks and indentation. This is probably overkill fo this example, but for complex formulas and programming, it is really a must. Both of them produces the same ouput.


enter image description here


    \partial{Q} = \frac{1}{2} \frac{ \sum{h_f} }{ \sum \left(  \frac{ h_{fi} }{ Q_i } \right)} 

\begin{equation}% Same code, just formated for ease of reading. Overkill.
    \partial{Q} = \frac{1}{2} 
             \sum{h_f} }{
                          \sum  \left(
                                    \frac{ h_{fi} }{ Q_i } 
  • My editor checks {} () and []. It's getting \begin \end and \if \fi to match up that gives me problems. Sometime I have to add braces around environments just to find the problem. Commented Jul 20, 2016 at 16:00

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