Question

Evaluate : `[(4sin30°, 2cos60°),(sin90°, 2cos0°)] [(4, 5),(5, 4)]`

Answer 1

`[(4sin30°, 2cos60°),(sin90°, 2cos0°)] [(4, 5),(5, 4)]`

sin30° = `(1)/(2), cos60° = (1)/(2)`
sin90° = 1 and cos0° = 1

∴ `[(4 xx 1/2, 2 xx 1/2),(1, 2 xx 1)] [(4, 5),(5, 4)]`

= `[(2, 1),(1, 2)] [(4, 5),(5, 4)]`

= `[(2 xx 4 + 1 xx 5, 2 xx 5 + 1 xx 4),(1 xx 4 + 2 xx 5, 1 xx 5 + 2 xx 4)]`

= `[(8 + 5, 10 + 4),(4 + 10, 5 + 8)]`

= `[(13, 14),(14, 13)]`.