y = - x
x = -6
y = -(-6) минус на минус, будет +
y = 6
y<em>= sinx/sinx</em> =1 , если sinx > 0 ( 0 < x < π ) ;
y<em>= -sinx/sinx</em>= -1 , если sinx < 0 ( π < x < 2π) .
5-2x<3(1-x)-12x
5-2x<3-3x-12x
-2x+15x<3-5
13x<-2
x<-2/13
x∈(-∞;-2/13)
Cos2x=-√3/2
2x=+-<span>5П/6+2Пn
x=+-</span><span>5П/12+Пn </span>
task/29398644 ----------------------
1.
a) √x - x^1/4= x√^(1/4)( x^1/4 -3*x^1/4 ) * * * √x =x ^1/2 ; x^(1/4) = ⁴√x * * * б)( x ^(1/4) -5) (x ^(1/4) +1 ) * * *x ^(1/4) =t ; t² +4t - 5 = ( t - t₁ )(t -t₂) = (t- 5)(t+1) * * * с) x -8 = (∛x)³-(2)³ = (∛x -2)( (∛x)² +2∛x +4) ; * * * a³- b³ =(a-b)(a²+ab+b²) * * *
2.
(15 +a√6)^(1/4) =(√6 -b) ^(1/2), где a,b ∈ Q* * * (√6 -b) ^(1/2) или √(√6 -b) * * * 15 +a√6 = (√6 -b)² ⇔15 +a√6 = 6 - 2b√6 +b² ⇔ 9 + a√6 = b² -2b√6 ⇒ { b² =9 ; a = -2b. ⇔ { b =± 3 ; a = -2b . ответ: (-3; 6) , (3 ; -6) .
3. * * * (a+b)² =a² +2ab+b² ; (a+b)³=a³ +3a²b+3ab² +b³ * * *
a) x^(2/3) -4x^(1/3)+4 =(x^(1/3) +2)² или иначе ( ∛x +2)² b) x +3x^(2/3)+3x^(1/3) +1 =(x^(1/3) +1 )³или иначе ( ∛x +1)³