A function f can be broadcast over all elements of an array (or matrix) by using the dot notation f.(matrix); for example:
arr = [1.0, 2.0, 3.0]
sin.(arr) #>
3-element Array{Float64,1}:
# 0.8414709848078965
# 0.9092974268256817
# 0.1411200080598672
Here is another example:
f(x,y) = x + 7y
f.(pi, arr)
#> 3-element Array{Float64,1}:
# 10.141592653589793
# 17.141592653589793
# 24.141592653589793
Broadcasting is very useful in Julia to write compact expressions with arrays and matrices.