3 and 4 .Determinants and Matrices
easy

यदि $A = \left[ {\begin{array}{*{20}{c}}0&1\\1&0\end{array}} \right],B = \left[ {\begin{array}{*{20}{c}}0&{ - i}\\i&0\end{array}} \right]$,  तो ${(A + B)^2}$=

A

${A^2} + {B^2}$

B

${A^2} + {B^2} + 2AB$

C

${A^2} + {B^2} + AB - BA$

D

इनमें से कोई नहीं

Solution

(a) $AB = \left[ {\begin{array}{*{20}{c}}0&1\\1&0\end{array}} \right]\,\left[ {\begin{array}{*{20}{c}}0&{ – i}\\i&0\end{array}} \right] = \left[ {\begin{array}{*{20}{c}}i&0\\0&{ – i}\end{array}} \right]$

तथा  $BA = \left[ {\begin{array}{*{20}{c}}0&{ – i}\\i&0\end{array}} \right]\,\left[ {\begin{array}{*{20}{c}}0&1\\1&0\end{array}} \right] = \left[ {\begin{array}{*{20}{c}}{ – i}&0\\0&i\end{array}} \right] = – AB$

$\therefore AB + BA = O$ अत ${(A + B)^2} = {A^2} + {B^2}$.

Standard 12
Mathematics

Similar Questions

Start a Free Trial Now

Confusing about what to choose? Our team will schedule a demo shortly.