Question

evaluate sin 18\cos72​

Answer 1

Answer:

sin18=cos(90-18)

sin18=cos72

answer is 1

Answer 2

$sin \alpha = cos(90 - \alpha )$

$\frac{cos(90 - 18)}{cos72} \\ \\ \frac{cos72}{cos72} = 1$

Hope this helped...... !!