Question

find the value
please do fast

Answer 1

sin (-75) = -sin (75)
We apply identity of Sin (A + B) where A=45 and B = 30
So, Sin (45 +30) = Sin45 × Cos 30 + Cos 45 × Sin30 =
$((1 \div \sqrt{2)} \times ( \sqrt3 \div 2 )) + ((1 \div \sqrt{2} ) \times (1 \div 2))$
=
$(\sqrt{3} + 1) \div 2 \sqrt{2}$
so this is yor ans