Question 91487
cos(x + {{{pi}}}) = cos(x)cos({{{pi}}}) - sin(x)sin({{{pi}}})
cos(x)(-1) - sin(x)(0)
-cos(x)
{{{graph(800,200,-13,13,-1,1,cos(x + 3.141592653))}}}
{{{graph(800,200,-13,13,-1,1,-cos(x))}}}