Cos(a-3pi)*sin(3pi/2+a)+2sin(a-pi)*cos(pi/2-a)+sin^2a =
= -cosa*(-cosa) +(-2sina)*(sina)+sin^2a = cos^2a-2sina^2a+sin^2a = cos^2a-sin^2a = cos2a
ОДЗ
2x-7>0; x>3.5
x+1>0;x>-1
x-19.0; x>19
общая ОДЗ x>19
log(3)(2x-7)-2log(3)(x+1)+log(3)(x-19)≥0
log(3)((2x-7)(x-19)/(x+1)^2))≥0
(2x-7)(x-19)/(x+1)^2≥1
(2x-7)(x-19)/(x+1)^2-1≥0
(2x^2-38x-7x+133-x^2-2x-1)/(x+1)^2≥0
(x^2-47x+132)/(x+1)^2≥0
(x-44)(x-3)/(x+1)^2≥0
----(-1)+++[3]----[44]+++
учитывая ОДЗ ответ x=[44;+∞)
А) n(m-k) б)5x(y-z) в) 3a(2d-1) г) -3а(1+2с)