Why is R creating a lumpy version of my periodic function

user_18237909 0
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I am trying to make a graph of the periodic function -23.5*cospi/4(x)+23.5
It gives the results I want in Desmos for reference.

However, when I code it as a function and plot it in ggplot, I get a weird-looking periodic function.

 x <- 0:32
    test <- data.frame(x, y=-23.5*cos(pi/4*x)+23.5)
    test2 <- function(x) -23.5*cos(pi/4*x)+23.5
    
    ggplot(data = test, mapping = aes(x,y))+
      geom_point()+
      stat_smooth(se = FALSE)

The points show as normal, but the stat_smooth gives this lumpy hunk of garbage.

ggplot2 r
1 Answers

As you want to graph a function I would suggest to use geom_function:

Note: For smoothness I doubled the default number of interpolation points n.

x <- 0:32
test <- data.frame(x, y = -23.5 * cos(pi / 4 * x) + 23.5)
test2 <- function(x) -23.5 * cos(pi / 4 * x) + 23.5

library(ggplot2)

ggplot() +
  geom_point(data = test, mapping = aes(x, y)) +
  geom_function(fun = test2, n = 202)

user_129938610
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