Brownian Motion

library(latex2exp)

set.seed(1213) # for reproducibility of random numbers
x <- cumsum(rnorm(100))
plot(x, type = "l", main = "Example of Using Expressions in Plots", ylab = TeX("$x_{i+1}=x_i+\\epsilon_{i+1}$"),
xlab = "step")

set.seed(1213) # for reproducibility of random numbers
x <- cumsum(rnorm(100))
plot(x, type = "l", main = "Example of Using Expressions in Plots", ylab = expression(x[i+1] ~ "=" ~ x[i]+epsilon[i+1]),
xlab = "step")

sessionInfo()

## R version 3.4.2 (2017-09-28)
## Platform: x86_64-pc-linux-gnu (64-bit)
## Running under: Linux Mint 18.2
## 
## Matrix products: default
## BLAS: /usr/lib/libblas/libblas.so.3.6.0
## LAPACK: /usr/lib/lapack/liblapack.so.3.6.0
## 
## locale:
##  [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C              
##  [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8    
##  [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8   
##  [7] LC_PAPER=en_US.UTF-8       LC_NAME=C                 
##  [9] LC_ADDRESS=C               LC_TELEPHONE=C            
## [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       
## 
## attached base packages:
## [1] stats     graphics  grDevices utils     datasets  methods   base     
## 
## other attached packages:
## [1] latex2exp_0.4.0
## 
## loaded via a namespace (and not attached):
##  [1] compiler_3.4.2  backports_1.1.2 magrittr_1.5    rprojroot_1.3-2
##  [5] tools_3.4.2     htmltools_0.3.6 yaml_2.1.16     Rcpp_0.12.15   
##  [9] stringi_1.1.6   rmarkdown_1.8   knitr_1.19      stringr_1.2.0  
## [13] digest_0.6.15   evaluate_0.10.1