Sin2x/since. ..................
( x - 1)(x^2 + 2x + 1) = 3x + 3
( x - 1)(x + 1)(x + 1) = 3( x + 1)
( x - 1)(x + 1)(x + 1) - 3( x + 1) = 0
( x + 1)( x^2 - 1 - 3) = 0
( x + 1)(x^2 - 4) = 0
x+ 1 = 0
x = - 1
x^2 - 4 = 0
x^2 = 4
x = 2
x = - 2
Ответ: x1 = - 1, x2 = 2, x3 = - 2.
1)sin^2a-1=sin^2a-sin^2a-cos^2a=cos^2a.
3) (sina+cosa)^2+(sina+cosa)^2=sin^2a+×sinacosa+cos^2a+sin^2a-2sinacosa+cos^2a=(sin^2a+cs^2a)(sin^2a+cos^2a)=1+1=2
Только ответы, без решения:
1)да
2)нет
3)нет
4)да