Question
Show that, if A and B are square matrices such that $AB = BA$, then ${(A + B)^2} = {A^2} + 2AB + {B^2}$.
Show that, if A and B are square matrices such that $AB = BA$, then ${(A + B)^2} = {A^2} + 2AB + {B^2}$.
Since, A and B are square matrices such that $AB = BA$.
$\therefore$ ${(A + B)^2} = (A + B) \cdot (A + B)$
$= {A^2} + AB + BA + {B^2}$
$= {A^2} + AB + AB + {B^2}$
$= {A^2} + 2AB + {B^2}$
NCERT & Exemplar solution for CBSE Class 12 Mathematics, Matrices. Curated by Sachin Sharma. Free for all students.