To find the product of a matrix and a vector, you need to ensure that the number of columns in the matrix is equal to the number of rows in the vector. Here, we have a matrix D with dimensions 3x2 and a vector n with dimensions 2x1.So, we can find D.n as follows:D = [1 -3;-3 0;4 9]n = [-2;-1]D.n = [1 -3;-3 0;4 9] . [-2;-1]= [(1)(-2) + (-3)(-1);(-3)(-2) + (0)(-1);(4)(-2) + (9)(-1)] = [-1;6;-17]Therefore, D.n = [-1;6;-17].
D.n meaning:
Nominal Diameter is also known as the mean or average outside diameter and is represented by DN.