# R/CreateLineAngle.R In LearnGeom: Learning Plane Geometry

#### Documented in CreateLineAngle

```#' Creates a vector to represent a line that passes through a point and forms certain angle with X axis
#'
#' \code{CreateLineAngle} creates a vector to represent a line that passes through a point and forms certain angle with X axis
#' @param P Vector containing the xy-coordinates of a point
#' @param angle Angle in degrees (0-360) for the line
#' @return Returns a vector which contains the slope and intercept of the defined line. If the angle is defined as 90, the slope is set to \code{Inf} and the intercept is replaced by the x-value for the line (which is a vertical line in this situation)
#' @examples
#' P <- c(0,0)
#' angle <- 45
#' Line <- CreateLineAngle(P, angle)
#' @export
CreateLineAngle<-function(P, angle){
if (angle%%90==0){
Line=c("Inf",P[1])
names(Line)=c("slope","x-value")
}
else{
m=tan(2*pi*angle/360)
n=P[2]-m*P[1]
Line=c(m,n)
names(Line)=c("slope","intercept")
}
class(Line) <- append(class(Line),"Line")
return(Line)
}
```

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LearnGeom documentation built on July 14, 2020, 5:06 p.m.