Using Addition, Subtraction and multiplication of a matrix by a real number to find an unknown matrix
Today we go a step further !
Our assignment is Ex.12(B) Nos.4, 5, 8, 9, 10 and 11
In all these sums you are expected to find an unknown matrix.
e.g.in No.4 you have to find A. So, what will you do ? Work out the matrix as you would any equation. In sum No.4, if we give the first matrixthe name P and the one after the = sign the name Q then the equation is P + 3A = Q. Therefore 3A = Q - P : work that out (remember when subtracting one matrix from another one, subtract each element of the second matrix from the corresponding element in the first matrix. Then in order to find A, A = (Q - P) / 3 (So divide each element in the matrix (Q - P) by 3 and then you will get A !
In sum 5(i): What will you do first ? work out the value of 2A (multiplying each element in matrix A by 2) and then add it to B. You do 5(ii) in the same way as you did No.4. The same applies to sums 8, 9 and 11.
In sum No.10 we come to the matrix "I" - do you remember what an "I" matrix is ?
It is an Identity Matrix or Unit Matrix. Please refer to page 160 No.7 to revise this.
The sum refers to a matrix of the order 2 x 2 - what does this mean ? It means that the matrix has 2 rows and 2 columns. It is like the first Identity matrix on page 160. I hope that is clear to you.
Once you know the above, do the sum as you have done the others.
All the best ! If you have any problem, please send me an e-mail at brelmiranda@gmail.com
Today we go a step further !
Our assignment is Ex.12(B) Nos.4, 5, 8, 9, 10 and 11
In all these sums you are expected to find an unknown matrix.
e.g.in No.4 you have to find A. So, what will you do ? Work out the matrix as you would any equation. In sum No.4, if we give the first matrixthe name P and the one after the = sign the name Q then the equation is P + 3A = Q. Therefore 3A = Q - P : work that out (remember when subtracting one matrix from another one, subtract each element of the second matrix from the corresponding element in the first matrix. Then in order to find A, A = (Q - P) / 3 (So divide each element in the matrix (Q - P) by 3 and then you will get A !
In sum 5(i): What will you do first ? work out the value of 2A (multiplying each element in matrix A by 2) and then add it to B. You do 5(ii) in the same way as you did No.4. The same applies to sums 8, 9 and 11.
In sum No.10 we come to the matrix "I" - do you remember what an "I" matrix is ?
It is an Identity Matrix or Unit Matrix. Please refer to page 160 No.7 to revise this.
The sum refers to a matrix of the order 2 x 2 - what does this mean ? It means that the matrix has 2 rows and 2 columns. It is like the first Identity matrix on page 160. I hope that is clear to you.
Once you know the above, do the sum as you have done the others.
All the best ! If you have any problem, please send me an e-mail at brelmiranda@gmail.com
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