1. cos 3x - = 1. 3
2. sin2 x + 5 sin x + 4 = 0.
3. cos* x + 4 cos x + 3 = 0.
4. ctg x +
4 + 5 = 0.
ctgx
5. tg x - tg2 x + 2 tg x - 2 = 0.

Question

Математика: 1. cos 3x - = 1. 3 2. sin2 x + 5 sin x + 4 = 0. 3. cos* x + 4 cos x + 3 = 0. 4. ctg x + 4 + 5 = 0. ctgx 5. tg x - tg2 x + 2 tg x - 2 = 0.

fghzghvyvvfsgv · Accepted Answer

Пошаговое объяснение:

4) ( aₙ ) : a₁ = 8 ; aₙ = 192 ; d = a₂ - a₁ = 16 - 8 = 8 ; d = 8 ;

aₙ = 192 = 8 + 8*( n - 1 ) ;

8*( n - 1 ) = 192 - 8 ;

8*( n - 1 ) = 184 ;

n - 1 = 184 : 8 ;

n - 1 = 23 ;

n = 24 ; S₂₄ = ( 8 + 192 )*24 /2 = 100 * 24 = 2400 ; S₂₄ = 2400.

5) ( aₙ ) : a₁₁ = 27 ; a₁₁ = a₁ + 10d ;

a₄ + a₁₈ = a₁ + 3d + a₁ + 17d = 2a₁ + 20d = 2* ( a₁ + 10d ) = 2* a₁₁ =

= 2*27 = 54 ; a₄ + a₁₈ = 54 .