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i get an error in \begin{equation}, i write long equation and split it using \\. it shows an error

 Package pgfplots Warning: running in backwards compatibility mode (unsuitable
 tick labels; missing features). Consider writing \pgfplotsset{compat=1.7} into
 your preamble

marked as duplicate by Torbjørn T., user13907, Zarko, Przemysław Scherwentke, moewe Dec 31 '15 at 17:23

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    This is a warning. Not an error. Just write \pgfplotsset{compat=1.7} after the loading of pgfplots in your preamble. You should consider updating your system as the current version is 1.12 I believe. Anyway, this has nothing to do with your equation. Note that you can not just split an equation by \\. You have to use a split or align or similar environment. – LaRiFaRi Dec 23 '15 at 7:43
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    If you want to get any real help here, we will need an MWE which produces the problems you are facing. – LaRiFaRi Dec 23 '15 at 7:45
  • Consider using \multline (en.wikibooks.org/wiki/LaTeX/…) – Karlo Dec 23 '15 at 8:04