1. Defining matrices. The function matrix(x, nrow, ncol) can be used to create a matrix object in R. The nrow and ncol parameters specify the number of rows and columns of the matrix. Additionally, x is a vector of values that is transformed into the matrix.

Start by defining a variable, vector, that consists of the integers from 1 to 20 using 1:20. Use matrix() to transform that variable into a 4x5 matrix.