Write the following expressions (or sets of expressions) in matrix/vector notation: (a) X N i=1 aibi (b) aibj (i = 1, , N; j = 1, , J) (c) X J j=1 aijxj (i = 1, ..., N) (d) X J j=1 aij bjk (i = 1, ..., N; k = 1, ..., K) (e) X J j=1 X K k=1 aij bjkckm (i = 1, ...N; m = 1, ..., M) (f) X N i=1 X N j=1 aijxixj