Q. D=[1−105] and B=[140524]Let H=DB. Find H.H=
Understand matrix multiplication: Understand matrix multiplication. Matrix multiplication involves taking the rows of the first matrix D and columns of the second matrix B and performing dot products to get the entries of the resulting matrix H. The number of columns in the first matrix must equal the number of rows in the second matrix for the multiplication to be defined. In this case, D is a 2×2 matrix and B is a 2×3 matrix, so the multiplication is defined and will result in a 2×3 matrix.
Perform first row multiplication: Perform the multiplication for the first row of H. The first row of H will be obtained by multiplying the first row of D by each column of B. H[1,1]=(1×1)+(0×4)=1H[1,2]=(1×0)+(0×5)=0H[1,3]=(1×2)+(0×4)=2 So the first row of H is [1,0,2].
Perform second row multiplication: Perform the multiplication for the second row of H. The second row of H will be obtained by multiplying the second row of D by each column of B. H[2,1]=(−1×1)+(5×4)=−1+20=19H[2,2]=(−1×0)+(5×5)=0+25=25H[2,3]=(−1×2)+(5×4)=−2+20=18 So the second row of H is [19,25,18].
More problems from Unions and intersections of sets