Question

If A = `[(sec60°, cos90°),(-3tan45°, sin90°)] and "B" = [(0, cos45°),(-2, 3sin90°)]` Find : A² 

Answer 1

Given
A = `[(sec60°, cos90°),(-3tan45°, sin90°)]`
and
B = `[(0, cos45°),(-2, 3sin90°)]`

A = `[(sec60° , cos90°),(-3tan45°, sin90°)] = [(2, 0),(3, 1)]`   ...(∵  sec60° = 2, cos90° = 0, tan45° = 1, sin90° = 1)

B = `[(0, cos45°),(-2, 3sin90°)] = [(0, 1),(-2, 3)]` ...(∵ cot45° = 1)

A² = A x A = `[(2, 0),(-3, 1)][(2, 0),(-3, 1)]`

= `[(4 + 0, 0 + 0),(-6 - 3, 0 + 1)]`

= `[(4, 0),(-9,  1)]`.