Practice

1. Write a loop that calculates 12-factorial

factorial <- function(num){
  total = num
  while (num>1){
    total = total*(num-1)
    num = num - 1
  }
  return(total)
}
factorial(12)

## [1] 479001600

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

seq(20,50,5)

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

3. Create the function “quadratic” 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.

quadratic <- function(a,b,c){
  delta = b^2-4*a*c
  if(delta > 0){
    x1 = (-b-sqrt(delta))/(2*a)
    x2 = (-b+sqrt(delta))/(2*a)
    roots = c(x1,x2)
  }
  else if(delta == 0){
    x = -b/(2*a)
    roots = c(x)
  }
  else{
    roots = "No real Roots"
  }
  return(roots)
}
quadratic(1,6,5)

## [1] -5 -1