To calculate the inverse tangent value of the input numeric value in R, use the atan() function.
atan() in R
The atan() is an inbuilt R trigonometric function that returns the radian arctangent of number data. The atan() method is used to calculate the inverse tangent value of the numeric value passed to it as an argument.
Syntax
atan(x)
Parameters
The atan() function takes x as an input value.
Example
Calculate the inverse tangent of a value.
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.
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, which will create 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
Applying atan() function to a Vector
To define a Vector in R, use the c() function. Then pass that vector 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
Passing a pi to the atan() function
The pi is an inbuilt 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
That is it for atan() function in R programming.