Week 1 assignment

Jian Quan Chen

##1. Write a loop that calculates 12-factorial

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

## [1] 479001600

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

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

## [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) {
  discriminant <- b^2 - 4*a*c 
  if (discriminant >= 0) {
    solution1 <- (-b + sqrt(discriminant)) / (2*a)
    solution2 <- (-b - sqrt(discriminant)) / (2*a)
    print(solution1)
    print(solution2)
    }
  else {
    print("The equation has no real solution")
  }
}
quadratic(2,10,-3)

## [1] 0.2838822
## [1] -5.283882

Note that the echo = FALSE parameter was added to the code chunk to prevent printing of the R code that generated the plot.