Question

$\bf\: Cos15\degree - Cos75\degree$​

Answer 1

Answer:

1/root2

Step-by-step explanation:

Cos15° - cos75°

Using, CosD - CosC = 2 sin(C+D)/2 × Sin(C-D)/2

= 2Sin(75+15)/2 × sin(75-15)/2

= 2 × sin45°×sin30°

= 2 × 1/root2 × 1/2

= 1/root2