add.fxn <- function(x,y){
x+y
}
add.fxn(3,4)

sides=c(3,4)
hyp.fxn <- function(x){
h=sqrt(sum(sides^2))
}
hyp.fxn(sides)

f.bad <- function(x,y){
 z1=2*x+y
 z2=x+2*y
 z3=2*x+2*y
 z4=x/y
}

f.bad(1,2)

f.good <- function(x,y){
 z1=2*x + y
 z2=x + 2*y
 z3=2*x + 2*y
 z4=x/y
 return(c(z1,z2,z3,z4))
}

f.good(1,2)

f2 <- function(x,y){
  z1=x+y
  z2=x+2*y
  list(z1,z2) 
}

f2(2,5)

# rnorm() will generate n random values from a normal distribution with mean=0
# and sd=1 unless mu and sd are specified. ?rnorm for help on the family
# of commands (random, quantile, density and probability commands)
# concerning specified distributions

x=rnorm(10)
x
x
x=rnorm(10)
x
x=rnorm(10)
x
y=rnorm(10)
y
y=rnorm(10)
y
y=rnorm(10)
y

set.seed(0)
x=rnorm(10)
set.seed(0)
y=rnorm(10)
x
y