ch4ex12

library(dplyr)

## 
## Attaching package: 'dplyr'

## The following objects are masked from 'package:stats':
## 
##     filter, lag

## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union

library(ggplot2)
#a Power() Function
Power <- function() {
  2^3
}

Power()

## [1] 8

#b Power2() Function
Power2 <- function(x, a) {
  x^a
}

Power2(3, 8)

## [1] 6561

#c Power2() Applied
Power2(10, 3)

## [1] 1000

Power2(8, 17)

## [1] 2.2518e+15

Power2(131, 3)

## [1] 2248091

#d Power3() Function
Power3 <- function(x, a) {
  result <- x^a
  result
}

Power3(3, 8)

## [1] 6561

#e Power3() Applied
data.frame(x = 1:10, y = Power3(1:10, 2)) %>%
  ggplot(aes(x = x, y = log(y))) + 
  geom_point() + 
  geom_line() + 
  scale_x_continuous(breaks = 1:10, minor_breaks = NULL)

#f PlotPower() Function
PlotPower <- function(x, a, col = "black") {
  ggplot(mapping = aes(x = x, y = x^a)) + 
    geom_point(col = col) + 
    geom_line(col = col) + 
    scale_x_continuous(labels = scales::comma_format()) +
    scale_y_continuous(labels = scales::comma_format()) +
    theme_light() + 
    labs(title = paste0("Plot of f(x) = x^", as.character(a), " (for x between ", min(x), " and ", max(x), ")"), 
         subtitle = "Created using the 'PlotPower()' function")
}
PlotPower(1:20, 3)

PlotPower(x = seq(1, 500, 10), 
          a = 2, 
          col = "deepskyblue3")