求r语言第四个问题的答案，图例实在不会加注

# 安装和加载必要的包
install.packages("ggplot2")
library(ggplot2)

# 创建数据
x <- seq(-10, 10, length.out = 100)
y <- x^3 + sin(x) * cos(x)
data <- data.frame(x, y)

# 绘制函数图形
plot <- ggplot(data, aes(x, y)) +
  geom_line(color = "blue", size = 1) +
  labs(x = "自变量 X", y = "函数 Y", title = "示意图") +
  theme_minimal()

# 显示图形
print(plot)