2 cos 50° cos 40° - 2 sin 95° sin 85° =

2 cos 50° cos 40° – 2 sin 95° sin 85° =

Jawaban:

-1

Penjelasan dengan langkah-langkah:

= $2 times frac{1}{2} times cos(10^o) + cos(90^o) - 2 times frac{1}{2} times cos(10^o) - cos(180^o )$

= $cos(10^o) + 0 - cos(10^o ) - ( - 1)$

= $cos(10 ^o) - cos(10^o ) + 1$

= $cos(10 ^o ) - cos(10 ^o ) - 1$

= $- 1$