问题
In RStudio rmarkdown equation symbols not reproduced in Word. When I click Knit Word this
"$A = \pi*r^{2}$"
becomes this in the Word doc
"? = ? * ?^2"
no problem with html, pdf
来源：https://stackoverflow.com/questions/26719753/rmarkdown-equation-in-word-non-numbers-are-question-marks