What is cos (π + ø) equivalent to?
1 Answer
Feb 28, 2018
Explanation:
#"using the "color(blue)"addition formula for cosine"#
#•color(white)(x)cos(A+B)=cosAcosB-sinAsinB#
#rArrcos(pi+phi)#
#=cospicosphi-sinpisinphi#
#=(-1)cosphi-(0)sinphi#
#=-cosphi#
