Recent content by phykb

Problem (1), (3): i have no idea Problem (2): question...cos(x)cos(y)cos(t)-cos(x)sin(y)sin(t)-sin(x)cos(y)sin(t)-sin(x)sin(y)cos(t)=cos(y) (cos(t) cos(x)-sin(t) sin(x))-sin(y) (sin(t) cos(x)+cos(t) sin(x))=cos(x+y+t)? if answer=yes, I'm ok with this problem, i solve this problem! Please...

Please help me with them problems: 1) if z^3=1, show that (1-z)(1-z^2)(1-z^4)(1-z^5)=9, zEC 2) if cos(x)+cos(y)+cos(t)=0, sin(x)+sin(y)+sin(t)=0 show that cos(3x)+cos(3y)+cos(3t)=3cos(x+y+t) 3)show that, the roots the equations (1+z)^(2n) +(1-z)^(2n)=0, nEN, zEC are given by the relation...