Разложить на множители: -20x²y³-5x⁴y

-5у(4+)

-20х² у³ -5х⁴у = -5х² у (4у² +х²)

Триганометрические, составитель ошибся

а)sin x = ✓3/2

x = (-1)ⁿ π/3 + πn

б)cos x = -3/5

x = ±arccos(-3/5) + 2πk

x = ±(π-arccos(3/5)+2πk

в)2cos²x+cosx - 1 = 0

cos x = t

2t²+t-1 = 0

Так как a-b+c = 0(2-1-1 = 0):

t1 = -1

t2 = -c/a = 1/2

1)cos x = -1

x = π+2πn

2)cos x = 1/2

x = ±π/3 + 2πn

г)sinx + sin 3x + sin 5x = 0

sin3x + sin5x + sinx = 0

sin3x + 2sin3x • cos2x = 0

sin3x(1+2cos2x) = 0

1)sin 3x = 0

3x = πk

x = π/3 k

2)1+2cos2x = 0

2cos2x = -1

cos2x = -1/2

2x = ±(π-arccos(1/2) + 2πk

x = ±1/2(π-π/3)+πk

x = ±1/2(2π/3)+πk

x = ±π/3 + πk

1,(18)=1+0,(18)

0,(18)=x

18,(18)=100x

18+0,(18)=100x

18+x=100x

18=99x

x=18/99

x=2/11

0,(18)=2/11

 

  1,(18)=1+0,(18) =1+2/11=13/11

 

 

2,(27)=7+0,(27)

0,(27)=x

27,(27)=100x

27+0,(27)=100x

27+x=100x

27=99x

x=27/99

x=3/11

0,(27)=3/11

  1,(27)=1+0,(27) =1+3/11=14/11

 

 

0,(13)=x

13,(13)=100x

13+0,(13)=100x

13+x=100x

13=99x

x=13/99

0,(13)=13/99

 

 

 

2,(23)=7+0,(23)

0,(23)=x

23,(23)=100x

23+0,(23)=100x

23+x=100x

23=99x

x=23/99

x=23/99

0,(23)=23/99

  2,(23)=2+0,(23) =2+23/99