Question

evalvate sin 18°÷cos 72°​

Answer 1

sin18/cos72

sin(90-72)/cos72

sin72/cos72

1

ans is 1

Answer 2

sin18° ÷ cos72°

= sin18° ÷ cos(90-18)°

= sin18° ÷ sin18° {cos(90-θ)=sinθ}

= (sin18°/sin18°)

= 1