How do you simplify # cos (pi - theta)#?
2 Answers
Aug 18, 2016
Explanation:
While a different answer mentions the unit circle, another way of arriving at the solution is to use the identity
along with the fact that
With that, we have
#=cos(pi)cos(-theta)-sin(pi)sin(-theta)#
#=(-1)cos(-theta) - 0sin(-theta)#
#=-cos(-theta) - 0#
#=-cos(-theta)#
#=-cos(theta)#
