Answer
Verified
426.3k+ views
Hint: For any general 2 x 2 matrix, \[M=\left[ \begin{matrix}
a & b \\
c & d \\
\end{matrix} \right]\], \[{{M}^{2}}=\left[ \begin{matrix}
a & b \\
c & d \\
\end{matrix} \right]\times \left[ \begin{matrix}
a & b \\
c & d \\
\end{matrix} \right]=\left[ \begin{matrix}
{{a}^{2}}+bc & ab+bd \\
ca+dc & cb+{{d}^{2}} \\
\end{matrix} \right]\]. So, to find \[{{A}^{2}}\], use this formula of \[{{M}^{2}}\] by considering a = i, b = 0, c = 0 and d = i.
We are given a 2 x 2 matrix, \[A=\left[ \begin{matrix}
i & 0 \\
0 & i \\
\end{matrix} \right]\]
Here, we have to find \[{{A}^{2}}\].
Let us take the matrix given in the question,
\[A=\left[ \begin{matrix}
i & 0 \\
0 & i \\
\end{matrix} \right]\] which is a 2 x 2 matrix as it has 2 rows and 2 columns.
Let us taken the general 2 x 2 matrix, that is
\[M=\left[ \begin{matrix}
a & b \\
c & d \\
\end{matrix} \right]\]
Now, we know that \[{{M}^{2}}=M\times M....\left( i \right)\]
By, putting the general 2 x 2 matrix in place of M in the right hand side (RHS) of the equation (i), we get,
\[{{M}^{2}}={{\left[ \begin{matrix}
a & b \\
c & d \\
\end{matrix} \right]}_{2\times 2}}\times {{\left[ \begin{matrix}
a & b \\
c & d \\
\end{matrix} \right]}_{2\times 2}}\]
We know that matrix multiplication is carried out by multiplying rows of the first matrix to columns of the second matrix. Therefore, we get above expression as,
\[{{M}^{2}}=\left[ \begin{matrix}
a\times a+b\times c & a\times b+b\times d \\
c\times a+d\times c & c\times b+d\times d \\
\end{matrix} \right].....\left( ii \right)\]
By simplifying the above expression, we get,
\[{{M}^{2}}=\left[ \begin{matrix}
{{a}^{2}}+bc & ab+bd \\
ca+dc & cb+{{d}^{2}} \\
\end{matrix} \right]\]
Now, we will compare the matrix given in the question, that is \[A=\left[ \begin{matrix}
i & 0 \\
0 & i \\
\end{matrix} \right]\] with general 2 x 2 matrix \[M=\left[ \begin{matrix}
a & b \\
c & d \\
\end{matrix} \right]\] , so we will get,
\[\begin{align}
& a=i \\
& b=0 \\
& c=0 \\
& d=i \\
\end{align}\]
Now, to get the value of \[{{A}^{2}}\], we will put these values of a, b, c and d in equation (ii). So we will get,
\[{{A}^{2}}=\left[ \begin{matrix}
{{\left( i \right)}^{2}}+0\times 0 & i\times \left( 0 \right)+\left( 0 \right)\times i \\
0\times i+i\times 0 & 0\times 0+{{\left( i \right)}^{2}} \\
\end{matrix} \right]\]
By simplifying the above expression, we get,
\[{{A}^{2}}=\left[ \begin{matrix}
{{i}^{2}} & 0 \\
0 & {{i}^{2}} \\
\end{matrix} \right]\]
As we know that it is an imaginary number and its value is \[\sqrt{-1}\]. Therefore, we get \[{{i}^{2}}=-1\].
Hence, we finally get \[{{A}^{2}}\] as \[\left[ \begin{matrix}
{{i}^{2}} & 0 \\
0 & {{i}^{2}} \\
\end{matrix} \right]=\left[ \begin{matrix}
-1 & 0 \\
0 & -1 \\
\end{matrix} \right]\].
Note: Students must note that to perform the matrix multiplication, the number of columns in the first matrix should be equal to the number of rows in the second matrix. Students should also remember that matrix multiplication is only carried out by multiplying rows of the first matrix by columns of the second matrix unlike in determinant. In determinant, multiplication can be carried out by multiplying row to row and column to column as well. Therefore, students must not confuse between multiplication of two matrices or two determinants. Also, take special care in taking the values of the variables a, b, c and d.
a & b \\
c & d \\
\end{matrix} \right]\], \[{{M}^{2}}=\left[ \begin{matrix}
a & b \\
c & d \\
\end{matrix} \right]\times \left[ \begin{matrix}
a & b \\
c & d \\
\end{matrix} \right]=\left[ \begin{matrix}
{{a}^{2}}+bc & ab+bd \\
ca+dc & cb+{{d}^{2}} \\
\end{matrix} \right]\]. So, to find \[{{A}^{2}}\], use this formula of \[{{M}^{2}}\] by considering a = i, b = 0, c = 0 and d = i.
We are given a 2 x 2 matrix, \[A=\left[ \begin{matrix}
i & 0 \\
0 & i \\
\end{matrix} \right]\]
Here, we have to find \[{{A}^{2}}\].
Let us take the matrix given in the question,
\[A=\left[ \begin{matrix}
i & 0 \\
0 & i \\
\end{matrix} \right]\] which is a 2 x 2 matrix as it has 2 rows and 2 columns.
Let us taken the general 2 x 2 matrix, that is
\[M=\left[ \begin{matrix}
a & b \\
c & d \\
\end{matrix} \right]\]
Now, we know that \[{{M}^{2}}=M\times M....\left( i \right)\]
By, putting the general 2 x 2 matrix in place of M in the right hand side (RHS) of the equation (i), we get,
\[{{M}^{2}}={{\left[ \begin{matrix}
a & b \\
c & d \\
\end{matrix} \right]}_{2\times 2}}\times {{\left[ \begin{matrix}
a & b \\
c & d \\
\end{matrix} \right]}_{2\times 2}}\]
We know that matrix multiplication is carried out by multiplying rows of the first matrix to columns of the second matrix. Therefore, we get above expression as,
\[{{M}^{2}}=\left[ \begin{matrix}
a\times a+b\times c & a\times b+b\times d \\
c\times a+d\times c & c\times b+d\times d \\
\end{matrix} \right].....\left( ii \right)\]
By simplifying the above expression, we get,
\[{{M}^{2}}=\left[ \begin{matrix}
{{a}^{2}}+bc & ab+bd \\
ca+dc & cb+{{d}^{2}} \\
\end{matrix} \right]\]
Now, we will compare the matrix given in the question, that is \[A=\left[ \begin{matrix}
i & 0 \\
0 & i \\
\end{matrix} \right]\] with general 2 x 2 matrix \[M=\left[ \begin{matrix}
a & b \\
c & d \\
\end{matrix} \right]\] , so we will get,
\[\begin{align}
& a=i \\
& b=0 \\
& c=0 \\
& d=i \\
\end{align}\]
Now, to get the value of \[{{A}^{2}}\], we will put these values of a, b, c and d in equation (ii). So we will get,
\[{{A}^{2}}=\left[ \begin{matrix}
{{\left( i \right)}^{2}}+0\times 0 & i\times \left( 0 \right)+\left( 0 \right)\times i \\
0\times i+i\times 0 & 0\times 0+{{\left( i \right)}^{2}} \\
\end{matrix} \right]\]
By simplifying the above expression, we get,
\[{{A}^{2}}=\left[ \begin{matrix}
{{i}^{2}} & 0 \\
0 & {{i}^{2}} \\
\end{matrix} \right]\]
As we know that it is an imaginary number and its value is \[\sqrt{-1}\]. Therefore, we get \[{{i}^{2}}=-1\].
Hence, we finally get \[{{A}^{2}}\] as \[\left[ \begin{matrix}
{{i}^{2}} & 0 \\
0 & {{i}^{2}} \\
\end{matrix} \right]=\left[ \begin{matrix}
-1 & 0 \\
0 & -1 \\
\end{matrix} \right]\].
Note: Students must note that to perform the matrix multiplication, the number of columns in the first matrix should be equal to the number of rows in the second matrix. Students should also remember that matrix multiplication is only carried out by multiplying rows of the first matrix by columns of the second matrix unlike in determinant. In determinant, multiplication can be carried out by multiplying row to row and column to column as well. Therefore, students must not confuse between multiplication of two matrices or two determinants. Also, take special care in taking the values of the variables a, b, c and d.
Recently Updated Pages
Three beakers labelled as A B and C each containing 25 mL of water were taken A small amount of NaOH anhydrous CuSO4 and NaCl were added to the beakers A B and C respectively It was observed that there was an increase in the temperature of the solutions contained in beakers A and B whereas in case of beaker C the temperature of the solution falls Which one of the following statements isarecorrect i In beakers A and B exothermic process has occurred ii In beakers A and B endothermic process has occurred iii In beaker C exothermic process has occurred iv In beaker C endothermic process has occurred
The branch of science which deals with nature and natural class 10 physics CBSE
The Equation xxx + 2 is Satisfied when x is Equal to Class 10 Maths
Define absolute refractive index of a medium
Find out what do the algal bloom and redtides sign class 10 biology CBSE
Prove that the function fleft x right xn is continuous class 12 maths CBSE
Trending doubts
Change the following sentences into negative and interrogative class 10 english CBSE
Write an application to the principal requesting five class 10 english CBSE
What is the z value for a 90 95 and 99 percent confidence class 11 maths CBSE
Fill the blanks with proper collective nouns 1 A of class 10 english CBSE
Write a letter to the principal requesting him to grant class 10 english CBSE
The Equation xxx + 2 is Satisfied when x is Equal to Class 10 Maths
How do you solve x2 11x + 28 0 using the quadratic class 10 maths CBSE
Select the word that is correctly spelled a Twelveth class 10 english CBSE
What is a collective noun for bees class 10 english CBSE