The atan() function in R is “used to return inverse tangent value of a numeric value”. For example, atan(1) returns 0.7853982 radians.
Syntax
atan(number)
Parameters
number: It’s a number as a numeric value.
Return value
The atan() function returns the inverse tangent of a number (radians) sent as a parameter. It is between [-pi/2,pi/2] in radians.
Example 1: How to use the atan() function
v1 <- -1
v2 <- 0.5
v3 <- 0
atan(v1)
atan(v2)
atan(v3)
Output
[1] -0.7853982
[1] 0.4636476
[1] 0
If you pass the 0 to the atan() function, it will return 0.
Example 2: Using atan() function with a Vector
To apply atan() function to a vector, you can use the c() function to create a vector and then pass it to the atan() function.
rv <- c(-1, 0.5, 0, 0.5, 1)
atan(rv)
Output
[1] -0.7853982 0.4636476 0.0000000 0.4636476 0.7853982
Example 3: Passing a pi to the atan() function
The pi is a built-in constant in R programming, and its value is 3.141593.
Let’s find the pi constant’s atan() value.
atan(pi)
Output
[1] 1.262627
Let’s see another example of pi.
atan(pi / 4)
Output
[1] 0.6657738
Plot the atan() function to a graph
We can use the seq() function to create a series of values and pass that to the plot() function, creating a line chart.
dt <- seq(-1, 1, by = 0.01)
plot(dt, atan(x), typ = "l", col = "red")
abline(v = 0, lty = 6, col = "blue")
Output
That is it for this tutorial.

Krunal Lathiya is a Software Engineer with over eight years of experience. He has developed a strong foundation in computer science principles and a passion for problem-solving. In addition, Krunal has excellent knowledge of Data Science and Machine Learning, and he is an expert in R Language.