Cos(pi/2+x) = -sinx
cos2x= cos^2x - sin^2x
-sinx = cos^2x - sin^2x
cos^2x =1 - sin^2x
-sinx = 1-sin^2x - sin^2x
2sin^2x - sinx - 1 =0
sinx = t
2t^2-t-1=0
D = 1 + 8 = 9
t1 = 1+3/4 = 4/4 = 1
t2 = -2/4 = -0.5
sinx = 1
x = pi/2+2pin
sinx = -0.5
x = -pi/6+2pin
x = -5pi/6+2pin
3a²-12a-2+8-8=3a²-12a+6-8=3(a²-4a+2)-8=3*6-8=10
Log₅ 1 =0
5⁰ = 1
1=1
Истинно
Решение во вложенииииииииииииииииииииии