Q. E=⎣⎡5−24311⎦⎤ and D=[−25−10]Let H=ED. Find H.H=
Matrix Multiplication: Matrix multiplication involves taking the rows of the first matrix E and the columns of the second matrix D and performing dot products to get the entries of the resulting matrix H. The dimensions of E are 3×2 and the dimensions of D are 2×2. Since the number of columns in E is equal to the number of rows in D, we can multiply these matrices. The resulting matrix H will have dimensions 3×2.
Entry in H[1,1]: To find the entry in the first row and first column of H, we take the dot product of the first row of E with the first column of D.H[1,1]=(5×−2)+(3×5)=−10+15=5.
Entry in H[1,2]: To find the entry in the first row and second column of H, we take the dot product of the first row of E with the second column of D.H[1,2]=(5×−1)+(3×0)=−5+0=−5.
Entry in H[2,1]: To find the entry in the second row and first column of H, we take the dot product of the second row of E with the first column of D.H[2,1]=(−2×−2)+(1×5)=4+5=9.
Entry in H[2,2]: To find the entry in the second row and second column of H, we take the dot product of the second row of E with the second column of D.H[2,2]=(−2×−1)+(1×0)=2+0=2.
Entry in H[3,1]: To find the entry in the third row and first column of H, we take the dot product of the third row of E with the first column of D.H[3,1]=(4×−2)+(1×5)=−8+5=−3.
Entry in H[3,2]: To find the entry in the third row and second column of H, we take the dot product of the third row of E with the second column of D.H[3,2]=(4×−1)+(1×0)=−4+0=−4.
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