-Cos110.Sin10-Sin70.Cos10=?

1 Answer
May 6, 2018

-cos 110^circ sin 10^circ - sin 70 ^circ cos 10^circ

= cos 70^circ sin 10^circ - sin 70 ^circ cos 10^circ

= sin(10^circ - 70^circ)

= sin(-60^circ)

= - sqrt{3}/2