I have a long formula that I need to break in the R documentation of a package or it trails off the right hand side of the page. Here's the formula:



\deqn{Cov(r_{ist}, r_{iuv})= [.5\rho_{ist}\rho_{iuv}(\rho_{isu}^2 + \rho_{isv}^2 + \rho_{itu}^2 + \rho_{itv}^2) + \rho_{isu}\rho_{itv}+ \rho_{isv}\rho_{itu}-(\rho_{ist}\rho_{isu}\rho_{isv} + \rho_{its}\rho_{itu}\rho_{itv}) + \rho_{ius}\rho_{iut}\rho_{iuv} + \rho_{ivs}\rho_{ivt}\rho_{ivu}]/n_i}




How can I break the formula and optionally indent it, though I'd settle for break it right now? 


Tyler Rinker


Note:  Cross posted here after no viable answer on stackoverflow: http://stackoverflow.com/questions/13780190/break-long-formula-r-documentation