(3cos(π-β)+sin(π/2+β))/cos(β+3π)=
=(3·(-cosβ)+cosβ)/cos(β+π+2π)=
=-2cosβ/(-cosβ)=-2;
используемые формулы:
cos(π-β)=-cosβ;
sin(π/2+β)=cosβ;
cos(π+β)=-cosβ;
cos(2π+β)=cosβ;
M^12-m^2
------------- =
m^4(m^3-1)
m^2(m^10-1) m^10-1
= ---------------- = -----------
m^4(m^3-1) m^6-m^4