# angle: Angle between two vectors In matlib: Matrix Functions for Teaching and Learning Linear Algebra and Multivariate Statistics

## Description

`angle` calculates the angle between two vectors.

## Usage

 `1` ```angle(x, y, degree = TRUE) ```

## Arguments

 `x` a numeric vector `y` a numeric vector `degree` logical; should the angle be computed in degrees? If `FALSE` the result is returned in radians

## Value

a scalar containing the angle between the vectors

`len`
 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31``` ```x <- c(2,1) y <- c(1,1) angle(x, y) # degrees angle(x, y, degree = FALSE) # radians # visually xlim <- c(0,2.5) ylim <- c(0,2) # proper geometry requires asp=1 plot( xlim, ylim, type="n", xlab="X", ylab="Y", asp=1, main = expression(theta == 18.4)) abline(v=0, h=0, col="gray") vectors(rbind(x,y), col=c("red", "blue"), cex.lab=c(2, 2)) text(.5, .37, expression(theta)) #### x <- c(-2,1) y <- c(1,1) angle(x, y) # degrees angle(x, y, degree = FALSE) # radians # visually xlim <- c(-2,1.5) ylim <- c(0,2) # proper geometry requires asp=1 plot( xlim, ylim, type="n", xlab="X", ylab="Y", asp=1, main = expression(theta == 108.4)) abline(v=0, h=0, col="gray") vectors(rbind(x,y), col=c("red", "blue"), cex.lab=c(2, 2)) text(0, .4, expression(theta), cex=1.5) ```