Алгебра: Выражение: (0,1m+2n²)(0,01m²-0,2mn²+4n⁴)

Выражение: (0,1m+2n²)(0,01m²-0,2mn²+4n⁴)

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Ответ:

Elizkap01

28.01.2020

Сумма кубов:

a³+b³=(a+b)(a²-ab+b²)

В данном случае a=0.1m

b=2n²

Сворачиваем обратно.

$(0.1m)^{3}+(2n^{2})^{3}=0.001m^{3}+8n^{6}$

4,4(83 оценок)

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Ответ:

aazzziizz

28.01.2020

5 arccos 1\2 + 3 arcsin (-корень из 2\2)
Оба значения табличные для cos и sin
$5 arccos \frac{1}{2} + 3 arcsin (- \frac{ \sqrt{2} }{2}) = \\ 5 * \frac{ \pi }{3} +3*(- \frac{ \pi }{4} ) = \\ \frac{5 \pi }{3} - \frac{3 \pi }{4} = \frac{11 \pi }{12}$

sin ( 4 arccos ( - 1\2) - 2 arcctg корень из 3\3)
Оба значения табличные для cos и ctg
$sin [ 4 arccos ( - \frac{1}{2}) - 2 arcctg \frac{ \sqrt{3} }{3} ] = \\ sin [4* \frac{2 \pi }{3} - 2* \frac{ \pi }{3} ] = \\ sin[ \frac{8 \pi }{3} - \frac{2 \pi }{3} ] = sin(2 \pi ) = 0$

6 sin^2x + 5cosx-7=0
Сначала использовать основное тригонометрическое тождество
$6 sin^2x + 5cosx-7=0 \\ 6 sin^2x + 5cosx-6 - 1 =0 \\ 6 sin^2x + 5cosx-6( sin^{2}x + cos^{2}x) - 1 =0 \\ 6 sin^2x + 5cosx-6 sin^{2}x - 6cos^{2}x - 1 =0 \\ 5cosx - 6cos^{2}x - 1 =0$
Это обыкновенное квадратное уравнение, в котором переменной является cos x
$- 6cos^{2}x +5cosx - 1 =0 \\ D = 25 - 4*(-6)*(-1) = 25 - 24 = 1 \\ cos x_{1} = \frac{-5-1}{-12} = \frac{1}{2} \\ cos x_{2} = \frac{-5+1}{-12} = \frac{1}{3} \\ x_{1} = \frac{+}{} \frac{ \pi }{3} + 2 \pi n \\ x_{2} = \frac{+}{} arccos \frac{1}{3} +2 \pi m$ , n,m∈Z

2sin^2x + sinx cosx - 3 cos^2x=0
Проверить, что $cos^{2} x$ не является корнем ( на ноль делить нельзя), а потом все уравнение почленно разделить на $cos^{2} x$
$cos^{2} x = 0$
$x = \frac{ \pi }{2} + \pi n \\ 2sin^2x + sinx cosx - 3 cos^2x=0 \\ 2sin^2 \frac{ \pi }{2} + sin \frac{ \pi }{2} cos \frac{ \pi }{2} - 3 cos^2 \frac{ \pi }{2}=0 \\ 1+0-0 \neq 0$
Не корень, можно делить
$2sin^2x + sinx cosx - 3 cos^2x=0 \\ \frac{2 sin^{2}x }{ cos^{2} x} + \frac{sinx cosx}{cos^{2} x} - \frac{3cos^{2} x}{cos^{2} x} =0 \\ 2 tg^{2}x +tgx-3 = 0$
Обыкновенное квадратное уравнение с переменной tg x
$2 tg^{2}x +tgx-3 = 0 \\ D = 1 - 4*2*(-3) = 25 \\ tg x_{1} = \frac{-1-5}{4} = -\frac{3}{2} \\ tg x_{2} = \frac{-1+5}{4} = 1 \\ x_{1} =arctg( -\frac{3}{2} ) + \pi n \\ x_{2} =\frac{ \pi }{4} + \pi m$
n,m ∈ Z

4,8(38 оценок)

Ответ:

Ирина29403

28.01.2020

0 және не знаю как гOTBET:

the afternoon, learn work

in lunchtime, I eat pizza and drink juice

in night, I watch TV or play mobile games

in weekend, I go to picnicin

Write the correct preposition, then complete the

sentences for you.

Write the correct preposition, then complete the

sentences for you.

Write the correct preposition, then complete the

sentences for you.

OTBET:

the afternoon, learn work

in lunchtime, I eat pizza and drink juice

in night, I watch TV or play mobile games

in weekend, I go to picnicin

OTBET:

the afternoon, learn work

in lunchtime, I eat pizza and drink juice

in night, I watch TV or play mobile games

in weekend, I go to picnicin

OTBET:

the afternoon, learn work

in lunchtime, I eat pizza and drink juice

in night, I watch TV or play mobile games

in weekend, I go to picnicin

OTBET:

the afternoon, learn work

in lunchtime, I eat pizza and drink juice

in night, I watch TV or play mobile games

in weekend, I go to picnicin

OTBET:

the afternoon, learn work

in lunchtime, I eat pizza and drink juice

in night, I watch TV or play mobile games

in weekend, I go to picnicin

OTBET:

the afternoon, learn work

in lunchtime, I eat pizza and drink juice

in night, I watch TV or play mobile games

in weekend, I go to picnicin

OTBET:

the afternoon, learn work

in lunchtime, I eat pizza and drink juice

in night, I watch TV or play mobile games

in weekend, I go to picnicin

OTBET:

the afternoon, learn work

in lunchtime, I eat pizza and drink juice

in night, I watch TV or play mobile games

in weekend, I go to picnicin

OTBET:

the afternoon, learn work

in lunchtime, I eat pizza and drink juice

in night, I watch TV or play mobile games

in weekend, I go to picnicin

OTBET:

the afternoon, learn work

in lunchtime, I eat pizza and drink juice

in night, I watch TV or play mobile games

in weekend, I go to picnicin

OTBET:

the afternoon, learn work

in lunchtime, I eat pizza and drink juice

in night, I watch TV or play mobile games

in weekend, I go to picnicin

Write the correct preposition, then complete the

sentences for you.

Write the correct preposition, then complete the

sentences for you.

Write the correct preposition, then complete the

sentences for you.

Write the correct preposition, then complete the

sentences for you.

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4,8(65 оценок)

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