__DUMB QUESTION __
Q1. If co-ordinates (x, y)one rotated by are augle

about the arigin the new coordinetes are represnted by matrix . How ?

Sol

^{n} :-

__Illustration__ :-

Q1. A =

and B 2

show that A B

B A .

__Sol__^{n} :- A . B =

=

B . A =

=

Q 2. Show taht A =

is ...of index 3.

__Solution__ :- A

^{2} =

A

^{3} = A

^{2} - A =

=

A

^{3} = 0 i.e. A

^{k} = 0

__DETERMINAATS__ :-

The experssion

is colled a determinant.

__Calculation of determinants__
= a

_{1} b

_{2} - a

_{2} b

_{1}
= a

_{1} (b

_{2} c

_{3} - b

_{2} b

_{3}) - b

_{1} (a

_{2} c

_{3} - c

_{2} a

_{3}) + c

_{1} (a

_{2} b

_{3} - b

_{2} c

_{3})