1) sin3a - sina / cos3a + cosa = tga
2sin(3a-a/2)*cos(3a+a/2) / 2cos(3a+a/2)*cos(3a-a/2) = tga
2sin(2a/2)*cos(4a/2) / 2cos(4a/2)*cos(2a/2) = tga
2sin(a)*cos(2a) / 2cos(2a)*cos(a) = tga
sin(a)/coa(a) = tga
2) Cos(a)-Cos(5a) / Sin(5a)+Sin(a)=tg(2a)
-2sin(a+5a/2)*sin(a-5a/2) / 2sin(5a+a/2)*cos(5a-a/2) = tg(2a)
-2sin(6a/2)*sin(-4a/2) / 2sin(6a/2)*cos(-4a/2) = tg(2a)
-2sin(3a)*sin(-2a) / 2sin(3a)*cos(-2a) = tg(2a)
-2sin(3a)*(-sin(2a)) / 2sin(3a)*cos(2a) = tg(2a)
2sin(3a)*sin(2a) / 2sin(3a)*cos(2a) = tg(2a)
sin(2a) / cos(2a) = tg(2a)
Объяснение:
1) (n-3)^2+(2n-3)(3+2n)=n^2-6n+9+4n^2-9=5n^2-6n
(n-3)^2=n^2-6n+9
(2n-3)(3+2n)=4n^2-9
2)(x+9)/3 - (x-1)/5=5 общий знаменатель 15
5(x+9)-3(x-1)=45
5x+45-3x+3=75
5x+45-3x+3-75=0
2x-27=0
2x=27
x=13.5