Posted by sally on Saturday, April 17, 2010 at 5:57pm.
4. Asked to simplify the expression sin(180−è), Rory volunteered the following solution:
sin(180−è) = sin 180−sin è, and, because sin 180 is zero, it follows that sin(180−è) is the same as −sin è. Is this answer correct? If not, what is a correct way to express sin(180−è)
in simpler form? Answer the same question for cos(180 − è).

Trig  bobpursley, Saturday, April 17, 2010 at 6:01pm
Isn't
Sin(A+B)=SinA Cos B + CosA sinB
sin(180e)= Sin180 Cos e + Cos180 sin e
= 0 sin e=sine