Algebra and Trigonometry

# Key Equations

 Identity matrix for a$2 × 2 2 × 2$matrix $I 2 =[ 1 0 0 1 ] I 2 =[ 1 0 0 1 ]$ Identity matrix for a$3 × 3 3 × 3$matrix $I 3 =[ 1 0 0 0 1 0 0 0 1 ] I 3 =[ 1 0 0 0 1 0 0 0 1 ]$ Multiplicative inverse of a$2 × 2 2 × 2$matrix