This is an inline equation: \( \displaystyle {{X}_{1}},\ldots ,{{X}_{n}} \).
\( \displaystyle \sum\limits_{i=1}^{n}{X_{i}^{2}}+\sum\limits_{i=1}^{n}{{{X}_{i}}{{Y}_{i}}}+\sum\limits_{i=1}^{n}{{{({{X}_{i}}-\bar{X})}^{2}}} \)
# Summary of cars
summary(cars)
## speed dist
## Min. : 4.0 Min. : 2
## 1st Qu.:12.0 1st Qu.: 26
## Median :15.0 Median : 36
## Mean :15.4 Mean : 43
## 3rd Qu.:19.0 3rd Qu.: 56
## Max. :25.0 Max. :120
Plot example:
plot(cars)