а) sin(a-pi)=-sin a
cos(a-Зpi/2)=-sin a
ctg(a-pi/2)=-tg а=-sin a/cos a
tg(pi+a)=tg a=sin a/cos a
sin(a-pi)+cos(a-Зpi/2)/ctg(a-pi/2)-tg(pi+a)= -sin a + (sin a *cos a)/sin a + tg a= -sin a + cos a + tg a
а) sin(a-pi)=-sin a
cos(a-Зpi/2)=-sin a
ctg(a-pi/2)=-tg а=-sin a/cos a
tg(pi+a)=tg a=sin a/cos a
sin(a-pi)+cos(a-Зpi/2)/ctg(a-pi/2)-tg(pi+a)= -sin a + (sin a *cos a)/sin a + tg a= -sin a + cos a + tg a