R HW 1

1. Write a loop that calculates 12-factorial

factorial <- 1
for (i in 1:12)
{
  factorial <- i * factorial
}
print(factorial)

## [1] 479001600

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

myvector <- c(4:10)
newvector <- myvector * 5
print(newvector)

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

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).

quad <- function(a,b,c)
{
  square <- (b**2)-(4*a*c) 
  first <-  (-b+sqrt(square))/(2*a)
  second <- (-b-sqrt(square))/(2*a)
  
  if (square <0)
  {
  return("No valid answers")
  } else
  {
  print(c(first, second))
  }
}

quad(1,2,1) # Should return -1 -1

## [1] -1 -1

quad(1,6,5) # Should return -1 -5

## [1] -1 -5

quad(1,1,1) # No valid answer

## Warning in sqrt(square): NaNs produced

## Warning in sqrt(square): NaNs produced

## [1] "No valid answers"