Question

show that sin 105°+cos 105° = cos 45°​

Answer 1

Answer:

LHS :

sin 105° + cos 105°

cos (90° - 105°) + cos 105°

cos 15° + cos 105°

cos C + cos D = 2(cos(C+D)/2)(cos(C-D)/2)

2cos(120°/2)cos(90°/2)

2cos60°cos45°

2(1/2)cos45°

cos45°

= RHS

Step-by-step explanation:

Hope it helps :)