如何在R中绘制切线？

# 定义函数来计算切线斜率
tangent_slope <- function(f, x) {
  h <- 0.0001  # 极限趋近于0的小值
  slope <- (f(x + h) - f(x - h)) / (2 * h)  # 切线斜率的计算公式
  return(slope)
}

library(ggplot2)

# 准备数据
x <- seq(-5, 5, by = 0.1)
y <- x^2

# 定义要绘制切线的点
point_x <- 2
point_y <- point_x^2

# 计算切线斜率
slope <- tangent_slope(function(x) x^2, point_x)

# 计算切线的y值
tangent_y <- point_y + slope * (x - point_x)

# 绘制图形
df <- data.frame(x = x, y = y, tangent_y = tangent_y)
ggplot(df, aes(x)) +
  geom_line(aes(y = y), color = "blue") +  # 绘制函数曲线
  geom_line(aes(y = tangent_y), color = "red") +  # 绘制切线
  geom_point(aes(x = point_x, y = point_y), color = "green")  # 绘制切线点