R Homework 1

R Bridge Week 1 Assignment

1. Write a loop that calculates 12 factorial

# Loop That calculate 12 factorial 
n_factional <- function(number){
  fract = 1
  #vector = 0
 
  # Check is vector is not negative 
  if (number < 0) {
    print("factorial negative is not defined")
    
  }
  else if (number == 0 ) {
    return(1)
  }
  else {
    for (i in 1:number){
      fract <- fract * i
    }
    return(fract)
  }
  
  
}


n_factional(12)

## [1] 479001600

2. Show how to create a numeric vector that contains the sequence from 20 to 50 by 5.

vector <- seq(from=20,to=50, by=5)
vector

## [1] 20 25 30 35 40 45 50

is.numeric(vector)

## [1] TRUE

3. Create the function “quad” that takes a trio of input numbers a, b, and c and solve the quadratic equation. The function should print as output the two solutions. Please run and test your answer for (1,2,1), (1,6,5) and (1,1,1).

# write quadratic equatio 
quad <- function(a,b,c) {
  ## provide baseline for equation
  print(paste0("You have chosen the quadratic equation ",
               a, "x^2 + ", b, "x + ", c, "."))
  # discriminant formula 
  f  <- (b^2) - (4*a*c)
  # discriminant is less than zero, the quadratic equations has no roots
  if(f < 0){
    return(paste0(" No real Number found"))
   # if discriminant is superior than zero, two intercepts will be  generated 
  }else if(f > 0){
    x_1 <- (-b + sqrt(f)) /(2*a)
    x_2 <- (-b - sqrt(f)) / (2*a)
    return(paste0("The Two x-intercepts are: ",
                  format(round(x_1, 5), nsmall = 5), " and ",
                  format(round(x_2, 5), nsmall = 5), "."))
    
    # if discriminant is equal zero
  }else{
    x <- (-b) /(2*a)
    return(x)
  }
   
}
# (1,2,1), (1,6,5) and (1,1,1).
vec1 <- quad(1,2,1)

## [1] "You have chosen the quadratic equation 1x^2 + 2x + 1."

vec1

## [1] -1

vec2 <- quad(1,-4,1)

## [1] "You have chosen the quadratic equation 1x^2 + -4x + 1."

vec2

## [1] "The Two x-intercepts are: 3.73205 and 0.26795."

vec3 <- quad(1,1,1)

## [1] "You have chosen the quadratic equation 1x^2 + 1x + 1."

vec3

## [1] " No real Number found"