zs

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

受欢迎的三角函数 >

88.2sin(x)-12.78=0.1*88.2cos(x)

解答

88.2 sin (x) - 12.78 = 0.1 \cdot 88.2 cos (x)

解答

x = 0.24435 \dots + 2 πn, x = π - 0.04501 \dots + 2 πn

+1

度数

x = 14.00032 \dots^{\circ} + 36 0^{\circ} n, x = 177.42086 \dots^{\circ} + 36 0^{\circ} n

求解步骤

88.2 sin (x) - 12.78 = 0.1 \cdot 88.2 cos (x)

两边进行平方

(88.2 sin (x) - 12.78)^{2} = (0.1 \cdot 88.2 cos (x))^{2}

两边减去

(0.188.2 cos (x))^{2}

(88.2 sin (x) - 12.78)^{2} - 77.7924 cos^{2} (x) = 0

使用三角恒等式改写

(- 12.78 + 88.2 sin (x))^{2} - 77.7924 cos^{2} (x)

使用毕达哥拉斯恒等式:

cos^{2} (x) + sin^{2} (x) = 1

cos^{2} (x) = 1 - sin^{2} (x)

= (- 12.78 + 88.2 sin (x))^{2} - 77.7924 (1 - sin^{2} (x))

化简

(- 12.78 + 88.2 sin (x))^{2} - 77.7924 (1 - sin^{2} (x)) : 7857.0324 sin^{2} (x) - 2254.392 sin (x) + 85.536

(- 12.78 + 88.2 sin (x))^{2} - 77.7924 (1 - sin^{2} (x))

(- 12.78 + 88.2 sin (x))^{2} : 163.3284 - 2254.392 sin (x) + 7779.24 sin^{2} (x)

使用完全平方公式:

(a + b)^{2} = a^{2} + 2 ab + b^{2}

a = - 12.78, b = 88.2 sin (x)

= (- 12.78)^{2} + 2 (- 12.78) \cdot 88.2 sin (x) + (88.2 sin (x))^{2}

化简

(- 12.78)^{2} + 2 (- 12.78) \cdot 88.2 sin (x) + (88.2 sin (x))^{2} : 163.3284 - 2254.392 sin (x) + 7779.24 sin^{2} (x)

(- 12.78)^{2} + 2 (- 12.78) \cdot 88.2 sin (x) + (88.2 sin (x))^{2}

去除括号:

(- a) = - a

= (- 12.78)^{2} - 2 \cdot 12.78 \cdot 88.2 sin (x) + (88.2 sin (x))^{2}

(- 12.78)^{2} = 163.3284

(- 12.78)^{2}

使用指数法则:

(- a)^{n} = a^{n},

若

n

是偶数

(- 12.78)^{2} = 12.7 8^{2}

= 12.7 8^{2}

12.7 8^{2} = 163.3284

= 163.3284

2 \cdot 12.78 \cdot 88.2 sin (x) = 2254.392 sin (x)

2 \cdot 12.78 \cdot 88.2 sin (x)

数字相乘:

2 \cdot 12.78 \cdot 88.2 = 2254.392

= 2254.392 sin (x)

(88.2 sin (x))^{2} = 7779.24 sin^{2} (x)

(88.2 sin (x))^{2}

使用指数法则:

(a \cdot b)^{n} = a^{n} b^{n}

= 88. 2^{2} sin^{2} (x)

88. 2^{2} = 7779.24

= 7779.24 sin^{2} (x)

= 163.3284 - 2254.392 sin (x) + 7779.24 sin^{2} (x)

= 163.3284 - 2254.392 sin (x) + 7779.24 sin^{2} (x)

= 163.3284 - 2254.392 sin (x) + 7779.24 sin^{2} (x) - 77.7924 (1 - sin^{2} (x))

乘开

- 77.7924 (1 - sin^{2} (x)) : - 77.7924 + 77.7924 sin^{2} (x)

- 77.7924 (1 - sin^{2} (x))

使用分配律:

a (b - c) = ab - a c

a = - 77.7924, b = 1, c = sin^{2} (x)

= - 77.7924 \cdot 1 - (- 77.7924) sin^{2} (x)

使用加减运算法则

- (- a) = a

= - 1 \cdot 77.7924 + 77.7924 sin^{2} (x)

数字相乘:

1 \cdot 77.7924 = 77.7924

= - 77.7924 + 77.7924 sin^{2} (x)

= 163.3284 - 2254.392 sin (x) + 7779.24 sin^{2} (x) - 77.7924 + 77.7924 sin^{2} (x)

化简

163.3284 - 2254.392 sin (x) + 7779.24 sin^{2} (x) - 77.7924 + 77.7924 sin^{2} (x) : 7857.0324 sin^{2} (x) - 2254.392 sin (x) + 85.536

163.3284 - 2254.392 sin (x) + 7779.24 sin^{2} (x) - 77.7924 + 77.7924 sin^{2} (x)

对同类项分组

= - 2254.392 sin (x) + 7779.24 sin^{2} (x) + 77.7924 sin^{2} (x) + 163.3284 - 77.7924

同类项相加:

7779.24 sin^{2} (x) + 77.7924 sin^{2} (x) = 7857.0324 sin^{2} (x)

= - 2254.392 sin (x) + 7857.0324 sin^{2} (x) + 163.3284 - 77.7924

数字相加/相减:

163.3284 - 77.7924 = 85.536

= 7857.0324 sin^{2} (x) - 2254.392 sin (x) + 85.536

= 7857.0324 sin^{2} (x) - 2254.392 sin (x) + 85.536

= 7857.0324 sin^{2} (x) - 2254.392 sin (x) + 85.536

85.536 - 2254.392 sin (x) + 7857.0324 sin^{2} (x) = 0

用替代法求解

85.536 - 2254.392 sin (x) + 7857.0324 sin^{2} (x) = 0

令

: sin (x) = u

85.536 - 2254.392 u + 7857.0324 u^{2} = 0

85.536 - 2254.392 u + 7857.0324 u^{2} = 0 : u = \frac{0.28692 \dots + 0.03878 \dots}{2}, u = \frac{0.28692 \dots - 0.03878 \dots}{2}

85.536 - 2254.392 u + 7857.0324 u^{2} = 0

两边除以

7857.0324

\frac{85.536}{7857.0324} - \frac{2254.392 u}{7857.0324} + \frac{7857.0324 u ^{2}}{7857.0324} = \frac{0}{7857.0324}

改写成标准形式

a x^{2} + b x + c = 0

u^{2} - 0.28692 \dots u + 0.01088 \dots = 0

使用求根公式求解

u^{2} - 0.28692 \dots u + 0.01088 \dots = 0

二次方程求根公式:

若

a = 1, b = - 0.28692 \dots, c = 0.01088 \dots

u_{1, 2} = \frac{- ( - 0.28692 \dots ) \pm ( - 0.28692 \dots ) ^{2} - 4 \cdot 1 \cdot 0.01088 \dots}{2 \cdot 1}

u_{1, 2} = \frac{- ( - 0.28692 \dots ) \pm ( - 0.28692 \dots ) ^{2} - 4 \cdot 1 \cdot 0.01088 \dots}{2 \cdot 1}

(- 0.28692 \dots)^{2} - 4 \cdot 1 \cdot 0.01088 \dots = 0.03878 \dots

(- 0.28692 \dots)^{2} - 4 \cdot 1 \cdot 0.01088 \dots

使用指数法则:

(- a)^{n} = a^{n},

若

n

是偶数

(- 0.28692 \dots)^{2} = 0.28692 \dots^{2}

= 0.28692 \dots^{2} - 4 \cdot 1 \cdot 0.01088 \dots

数字相乘:

4 \cdot 1 \cdot 0.01088 \dots = 0.04354 \dots

= 0.28692 \dots^{2} - 0.04354 \dots

0.28692 \dots^{2} = 0.08232 \dots

= 0.08232 \dots - 0.04354 \dots

数字相减:

0.08232 \dots - 0.04354 \dots = 0.03878 \dots

= 0.03878 \dots

u_{1, 2} = \frac{- ( - 0.28692 \dots ) \pm 0.03878 \dots}{2 \cdot 1}

将解分隔开

u_{1} = \frac{- ( - 0.28692 \dots ) + 0.03878 \dots}{2 \cdot 1}, u_{2} = \frac{- ( - 0.28692 \dots ) - 0.03878 \dots}{2 \cdot 1}

u = \frac{- ( - 0.28692 \dots ) + 0.03878 \dots}{2 \cdot 1} : \frac{0.28692 \dots + 0.03878 \dots}{2}

\frac{- ( - 0.28692 \dots ) + 0.03878 \dots}{2 \cdot 1}

使用法则

- (- a) = a

= \frac{0.28692 \dots + 0.03878 \dots}{2 \cdot 1}

数字相乘:

2 \cdot 1 = 2

= \frac{0.28692 \dots + 0.03878 \dots}{2}

u = \frac{- ( - 0.28692 \dots ) - 0.03878 \dots}{2 \cdot 1} : \frac{0.28692 \dots - 0.03878 \dots}{2}

\frac{- ( - 0.28692 \dots ) - 0.03878 \dots}{2 \cdot 1}

使用法则

- (- a) = a

= \frac{0.28692 \dots - 0.03878 \dots}{2 \cdot 1}

数字相乘:

2 \cdot 1 = 2

= \frac{0.28692 \dots - 0.03878 \dots}{2}

二次方程组的解是:

u = \frac{0.28692 \dots + 0.03878 \dots}{2}, u = \frac{0.28692 \dots - 0.03878 \dots}{2}

u = sin (x)

代回

sin (x) = \frac{0.28692 \dots + 0.03878 \dots}{2}, sin (x) = \frac{0.28692 \dots - 0.03878 \dots}{2}

sin (x) = \frac{0.28692 \dots + 0.03878 \dots}{2}, sin (x) = \frac{0.28692 \dots - 0.03878 \dots}{2}

sin (x) = \frac{0.28692 \dots + 0.03878 \dots}{2} : x = arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 πn, x = π - arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 πn

sin (x) = \frac{0.28692 \dots + 0.03878 \dots}{2}

使用反三角函数性质

sin (x) = \frac{0.28692 \dots + 0.03878 \dots}{2}

sin (x) = \frac{0.28692 \dots + 0.03878 \dots}{2}

的通解

sin (x) = a \Rightarrow x = arcsin (a) + 2 πn, x = π - arcsin (a) + 2 πn

x = arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 πn, x = π - arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 πn

x = arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 πn, x = π - arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 πn

sin (x) = \frac{0.28692 \dots - 0.03878 \dots}{2} : x = arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 πn, x = π - arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 πn

sin (x) = \frac{0.28692 \dots - 0.03878 \dots}{2}

使用反三角函数性质

sin (x) = \frac{0.28692 \dots - 0.03878 \dots}{2}

sin (x) = \frac{0.28692 \dots - 0.03878 \dots}{2}

的通解

sin (x) = a \Rightarrow x = arcsin (a) + 2 πn, x = π - arcsin (a) + 2 πn

x = arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 πn, x = π - arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 πn

x = arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 πn, x = π - arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 πn

合并所有解

x = arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 πn, x = π - arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 πn, x = arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 πn, x = π - arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 πn

将解代入原方程进行验证

将它们代入

88.2 sin (x) - 12.78 = 0.188.2 cos (x)

检验解是否符合

去除与方程不符的解。

检验

arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 πn

的解:

真

arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 πn

代入

n = 1

arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 π 1

对于

88.2 sin (x) - 12.78 = 0.188.2 cos (x)

代入

x = arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 π 1

88.2 sin (arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 π 1) - 12.78 = 0.1 \cdot 88.2 cos (arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 π 1)

整理后得

8.55799 \dots = 8.55799 \dots

\Rightarrow 真

检验

π - arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 πn

的解:

假

π - arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 πn

代入

n = 1

π - arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 π 1

对于

88.2 sin (x) - 12.78 = 0.188.2 cos (x)

代入

x = π - arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 π 1

88.2 sin (π - arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 π 1) - 12.78 = 0.1 \cdot 88.2 cos (π - arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 π 1)

整理后得

8.55799 \dots = - 8.55799 \dots

\Rightarrow 假

检验

arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 πn

的解:

假

arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 πn

代入

n = 1

arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 π 1

对于

88.2 sin (x) - 12.78 = 0.188.2 cos (x)

代入

x = arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 π 1

88.2 sin (arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 π 1) - 12.78 = 0.1 \cdot 88.2 cos (arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 π 1)

整理后得

- 8.81106 \dots = 8.81106 \dots

\Rightarrow 假

检验

π - arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 πn

的解:

真

π - arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 πn

代入

n = 1

π - arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 π 1

对于

88.2 sin (x) - 12.78 = 0.188.2 cos (x)

代入

x = π - arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 π 1

88.2 sin (π - arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 π 1) - 12.78 = 0.1 \cdot 88.2 cos (π - arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 π 1)

整理后得

- 8.81106 \dots = - 8.81106 \dots

\Rightarrow 真

x = arcsin (\frac{0.28692 \dots + 0.03878 \dots}{2}) + 2 πn, x = π - arcsin (\frac{0.28692 \dots - 0.03878 \dots}{2}) + 2 πn

以小数形式表示解

x = 0.24435 \dots + 2 πn, x = π - 0.04501 \dots + 2 πn

作图

流行的例子

1+sin(x)=2*cos(x)

1 + sin (x) = 2 \cdot cos (x)

sin(x)=0.75cos(x)

sin (x) = 0.75 cos (x)

tan (x) = 1.15

0.6 = cos^{2} (x)

10=sqrt(65)*sqrt(5)*cos(θ)

10 = 65 \cdot 5 \cdot cos (θ)