We can use the **`mutate()` function** in R programming to add new variables in the specified data frame. These new variables are added by performing the operations on present variables. 

Before using the `mutate()` function, you need to install the `dplyr` library. We can use the `mutate()` method to manipulate big datasets. `mutate()` is a rather simple method to use to manipulate datasets.
>```R 
>install.package("dplyr") 
>```
>This can be used to install the `dplyr` library. 
# 
## Syntax

```r
mutate(x, expr)
```

## Parameters
* **`x`**: Contains the data frame.
* **`expr`**: The operation to be performed on variables.

## Example 1
In the example below, we have a data frame `df` that contains four students' marks in `Maths` and `English`. Our major goal is to use the `mutate()` method and make a new data frame that contains the `totalMarks` column.

library(dplyr) #load the library
# Creating data frame
df <- data.frame( 
	studentname = c("Student1", "Student2", "Student3", "Student4"),
	Math = c(75, 58, 93, 66),
	Eng= c(44, 89, 89, NA)
)
# Calculate the total marks (totalMarks)
# sum of marks in Maths (Math) & English (Eng)
mutate(df, totalMarks = Math + Eng)

#   
## Example 2
In the example below, we are simply multiplying two columns, `COL1, COL2`, into a new column named `dotProduct`. We use the `mutate()` method to merge these three columns. 

library(dplyr) #load the library
# Creating data frame
df <- data.frame( 
	COL1 = c(5, 8, 9, 6),
	COL2= c(55, 6 , NA, 45) 
)
# Calculate the product (dotProduct) which is COL1*COL2
mutate(df, dotProduct = COL1 * COL2)

What is the mutate() function in R?

The mutate() function in R (from the dplyr library) adds new variables to a data frame by performing operations on existing ones.