1. Show that, when a is a scalar and x is a vector, match(a,x) is equivalent to min(which(x == a)). Discuss the uses of match and which in the case of the comparison of two vectors. Compare this with the use of %in%.
2. The Boolean expression x==y does not work well for floating-point numbers in that rounding errors may produce a FALSE answer. Compare it with the functions all.equal and identical.