Asked to simplify the expression sin(180−è), Rory volunteered the following solution:

Question

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).

Answer 1

try using letters like a,b,c instead of the special characters that are getting mangled.