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受欢迎的三角函数 >

45=57.7+arctan((3.5)/x)-arctan((175)/x)

解答

4 5^{\circ} = 57. 7^{\circ} + arctan (\frac{3.5}{x}) - arctan (\frac{175}{x})

解答

x = \frac{171.5 - 29287.82182 \dots}{0.45071 \dots}, x = \frac{171.5 + 29287.82182 \dots}{0.45071 \dots}

求解步骤

4 5^{\circ} = 57. 7^{\circ} + arctan (\frac{3.5}{x}) - arctan (\frac{175}{x})

交换两边

57. 7^{\circ} + arctan (\frac{3.5}{x}) - arctan (\frac{175}{x}) = 4 5^{\circ}

使用三角恒等式改写

57. 7^{\circ} + arctan (\frac{3.5}{x}) - arctan (\frac{175}{x})

使用和差化积恒等式:

arctan (s) - arctan (t) = arctan (\frac{s - t}{1 + s t})

= 57. 7^{\circ} + arctan (\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}})

57. 7^{\circ} + arctan (\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}}) = 4 5^{\circ}

将

57. 7^{\circ}

到右边

57. 7^{\circ} + arctan (\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}}) = 4 5^{\circ}

两边减去

57. 7^{\circ}

57. 7^{\circ} + arctan (\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}}) - 57. 7^{\circ} = 4 5^{\circ} - 57. 7^{\circ}

化简

57. 7^{\circ} + arctan (\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}}) - 57. 7^{\circ} = 4 5^{\circ} - 57. 7^{\circ}

化简

57. 7^{\circ} + arctan (\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}}) - 57. 7^{\circ} : arctan (\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}})

57. 7^{\circ} + arctan (\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}}) - 57. 7^{\circ}

同类项相加:

57. 7^{\circ} - 57. 7^{\circ} = 0

= arctan (\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}})

化简

4 5^{\circ} - 57. 7^{\circ} : - 12. 7^{\circ}

4 5^{\circ} - 57. 7^{\circ}

4, 1800

的最小公倍数:

1800

4, 1800

最小公倍数 (LCM)

4

质因数分解:

2 \cdot 2

4

4

除以

24 = 2 \cdot 2

= 2 \cdot 2

1800

质因数分解:

2 \cdot 2 \cdot 2 \cdot 3 \cdot 3 \cdot 5 \cdot 5

1800

1800

除以

21800 = 900 \cdot 2

= 2 \cdot 900

900

除以

2900 = 450 \cdot 2

= 2 \cdot 2 \cdot 450

450

除以

2450 = 225 \cdot 2

= 2 \cdot 2 \cdot 2 \cdot 225

225

除以

3225 = 75 \cdot 3

= 2 \cdot 2 \cdot 2 \cdot 3 \cdot 75

75

除以

375 = 25 \cdot 3

= 2 \cdot 2 \cdot 2 \cdot 3 \cdot 3 \cdot 25

25

除以

525 = 5 \cdot 5

= 2 \cdot 2 \cdot 2 \cdot 3 \cdot 3 \cdot 5 \cdot 5

2, 3, 5

都是质数，因此无法进一步因数分解

= 2 \cdot 2 \cdot 2 \cdot 3 \cdot 3 \cdot 5 \cdot 5

将每个因子乘以它在

4

或

1800

中出现的最多次数

= 2 \cdot 2 \cdot 2 \cdot 3 \cdot 3 \cdot 5 \cdot 5

数字相乘:

2 \cdot 2 \cdot 2 \cdot 3 \cdot 3 \cdot 5 \cdot 5 = 1800

= 1800

根据最小公倍数调整分式

将每个分子乘以其分母转变为最小公倍数所要乘以的同一数值

1800

对于

4 5^{\circ} :

将分母和分子乘以

450

4 5^{\circ} = \frac{18 0 ^{\circ} 450}{4 \cdot 450} = 4 5^{\circ}

= 4 5^{\circ} - 57. 7^{\circ}

因为分母相等，所以合并分式:

\frac{a}{c} \pm \frac{b}{c} = \frac{a \pm b}{c}

= \frac{18 0 ^{\circ} 450 - 10386 0 ^{\circ}}{1800}

同类项相加:

8100 0^{\circ} - 10386 0^{\circ} = - 2286 0^{\circ}

= \frac{- 2286 0 ^{\circ}}{1800}

使用分式法则:

\frac{- a}{b} = - \frac{a}{b}

= - 12. 7^{\circ}

arctan (\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}}) = - 12. 7^{\circ}

arctan (\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}}) = - 12. 7^{\circ}

arctan (\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}}) = - 12. 7^{\circ}

使用反三角函数性质

arctan (\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}}) = - 12. 7^{\circ}

arctan (x) = a \Rightarrow x = tan (a)

\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}} = tan (- 12. 7^{\circ})

tan (- 12. 7^{\circ}) = - tan (12. 7^{\circ})

tan (- 12. 7^{\circ})

利用以下特性:

tan (- x) = - tan (x)

tan (- 12. 7^{\circ}) = - tan (12. 7^{\circ})

= - tan (12. 7^{\circ})

\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}} = - tan (12. 7^{\circ})

\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}} = - tan (12. 7^{\circ})

解

\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}} = - tan (12. 7^{\circ}) : x = \frac{171.5 - 29287.82182 \dots}{0.45071 \dots}, x = \frac{171.5 + 29287.82182 \dots}{0.45071 \dots}

\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}} = - tan (12. 7^{\circ})

化简

\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}} : - \frac{171.5 x}{x ^{2} + 612.5}

\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}}

合并分式

\frac{3.5}{x} - \frac{175}{x} : - \frac{171.5}{x}

使用法则

\frac{a}{c} \pm \frac{b}{c} = \frac{a \pm b}{c}

= \frac{3.5 - 175}{x}

数字相减:

3.5 - 175 = - 171.5

= \frac{- 171.5}{x}

使用分式法则:

\frac{- a}{b} = - \frac{a}{b}

= - \frac{171.5}{x}

= \frac{- \frac{171.5}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}}

使用分式法则:

\frac{- a}{b} = - \frac{a}{b}

= - \frac{\frac{171.5}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}}

使用分式法则:

\frac{\frac{b}{c}}{a} = \frac{b}{c \cdot a}

\frac{\frac{171.5}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}} = \frac{171.5}{x ( 1 + \frac{3.5}{x} \cdot \frac{175}{x} )}

= - \frac{171.5}{x ( 1 + \frac{3.5}{x} \cdot \frac{175}{x} )}

\frac{3.5}{x} \cdot \frac{175}{x} = \frac{612.5}{x ^{2}}

\frac{3.5}{x} \cdot \frac{175}{x}

分式相乘:

\frac{a}{b} \cdot \frac{c}{d} = \frac{a \cdot c}{b \cdot d}

= \frac{3.5 \cdot 175}{xx}

数字相乘:

3.5 \cdot 175 = 612.5

= \frac{612.5}{xx}

xx = x^{2}

xx

使用指数法则:

a^{b} \cdot a^{c} = a^{b + c}

xx = x^{1 + 1}

= x^{1 + 1}

数字相加:

1 + 1 = 2

= x^{2}

= \frac{612.5}{x ^{2}}

= - \frac{171.5}{x ( \frac{612.5}{x ^{2}} + 1 )}

化简

1 + \frac{612.5}{x ^{2}} : \frac{x ^{2} + 612.5}{x ^{2}}

1 + \frac{612.5}{x ^{2}}

将项转换为分式:

1 = \frac{1 x ^{2}}{x ^{2}}

= \frac{1 \cdot x ^{2}}{x ^{2}} + \frac{612.5}{x ^{2}}

因为分母相等，所以合并分式:

\frac{a}{c} \pm \frac{b}{c} = \frac{a \pm b}{c}

= \frac{1 \cdot x ^{2} + 612.5}{x ^{2}}

乘以:

1 \cdot x^{2} = x^{2}

= \frac{x ^{2} + 612.5}{x ^{2}}

= - \frac{171.5}{\frac{x ^{2} + 612.5}{x ^{2}} x}

乘

x \frac{x ^{2} + 612.5}{x ^{2}} : \frac{x ^{2} + 612.5}{x}

x \frac{x ^{2} + 612.5}{x ^{2}}

分式相乘:

a \cdot \frac{b}{c} = \frac{a \cdot b}{c}

= \frac{( x ^{2} + 612.5 ) x}{x ^{2}}

约分:

x

= \frac{x ^{2} + 612.5}{x}

= - \frac{171.5}{\frac{x ^{2} + 612.5}{x}}

使用分式法则:

\frac{a}{\frac{b}{c}} = \frac{a \cdot c}{b}

= - \frac{171.5 x}{x ^{2} + 612.5}

- \frac{171.5 x}{x ^{2} + 612.5} = - tan (12. 7^{\circ})

在两边乘以

x^{2} + 612.5

- \frac{171.5 x}{x ^{2} + 612.5} = - tan (12. 7^{\circ})

在两边乘以

x^{2} + 612.5

- \frac{171.5 x}{x ^{2} + 612.5} (x^{2} + 612.5) = - tan (12. 7^{\circ}) (x^{2} + 612.5)

化简

- 171.5 x = - tan (12. 7^{\circ}) (x^{2} + 612.5)

- 171.5 x = - tan (12. 7^{\circ}) (x^{2} + 612.5)

解

- 171.5 x = - tan (12. 7^{\circ}) (x^{2} + 612.5) : x = \frac{171.5 - 29287.82182 \dots}{0.45071 \dots}, x = \frac{171.5 + 29287.82182 \dots}{0.45071 \dots}

- 171.5 x = - tan (12. 7^{\circ}) (x^{2} + 612.5)

展开

- tan (12. 7^{\circ}) (x^{2} + 612.5) : - tan (12. 7^{\circ}) x^{2} - 612.5 tan (12. 7^{\circ})

- tan (12. 7^{\circ}) (x^{2} + 612.5)

使用分配律:

a (b + c) = ab + a c

a = - tan (12. 7^{\circ}), b = x^{2}, c = 612.5

= - tan (12. 7^{\circ}) x^{2} + (- tan (12. 7^{\circ})) \cdot 612.5

使用加减运算法则

+ (- a) = - a

= - tan (12. 7^{\circ}) x^{2} - 612.5 tan (12. 7^{\circ})

- 171.5 x = - tan (12. 7^{\circ}) x^{2} - 612.5 tan (12. 7^{\circ})

交换两边

- tan (12. 7^{\circ}) x^{2} - 612.5 tan (12. 7^{\circ}) = - 171.5 x

将

171.5 x

para o lado esquerdo

- tan (12. 7^{\circ}) x^{2} - 612.5 tan (12. 7^{\circ}) = - 171.5 x

两边加上

171.5 x

- tan (12. 7^{\circ}) x^{2} - 612.5 tan (12. 7^{\circ}) + 171.5 x = - 171.5 x + 171.5 x

化简

- tan (12. 7^{\circ}) x^{2} - 612.5 tan (12. 7^{\circ}) + 171.5 x = 0

- tan (12. 7^{\circ}) x^{2} - 612.5 tan (12. 7^{\circ}) + 171.5 x = 0

改写成标准形式

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

- 0.22535 \dots x^{2} + 171.5 x - 138.03283 \dots = 0

使用求根公式求解

- 0.22535 \dots x^{2} + 171.5 x - 138.03283 \dots = 0

二次方程求根公式:

若

a = - 0.22535 \dots, b = 171.5, c = - 138.03283 \dots

x_{1, 2} = \frac{- 171.5 \pm 171. 5 ^{2} - 4 ( - 0.22535 \dots ) ( - 138.03283 \dots )}{2 ( - 0.22535 \dots )}

x_{1, 2} = \frac{- 171.5 \pm 171. 5 ^{2} - 4 ( - 0.22535 \dots ) ( - 138.03283 \dots )}{2 ( - 0.22535 \dots )}

171. 5^{2} - 4 (- 0.22535 \dots) (- 138.03283 \dots) = 29287.82182 \dots

171. 5^{2} - 4 (- 0.22535 \dots) (- 138.03283 \dots)

使用法则

- (- a) = a

= 171. 5^{2} - 4 \cdot 0.22535 \dots \cdot 138.03283 \dots

数字相乘:

4 \cdot 0.22535 \dots \cdot 138.03283 \dots = 124.42817 \dots

= 171. 5^{2} - 124.42817 \dots

171. 5^{2} = 29412.25

= 29412.25 - 124.42817 \dots

数字相减:

29412.25 - 124.42817 \dots = 29287.82182 \dots

= 29287.82182 \dots

x_{1, 2} = \frac{- 171.5 \pm 29287.82182 \dots}{2 ( - 0.22535 \dots )}

将解分隔开

x_{1} = \frac{- 171.5 + 29287.82182 \dots}{2 ( - 0.22535 \dots )}, x_{2} = \frac{- 171.5 - 29287.82182 \dots}{2 ( - 0.22535 \dots )}

x = \frac{- 171.5 + 29287.82182 \dots}{2 ( - 0.22535 \dots )} : \frac{171.5 - 29287.82182 \dots}{0.45071 \dots}

\frac{- 171.5 + 29287.82182 \dots}{2 ( - 0.22535 \dots )}

去除括号:

(- a) = - a

= \frac{- 171.5 + 29287.82182 \dots}{- 2 \cdot 0.22535 \dots}

数字相乘:

2 \cdot 0.22535 \dots = 0.45071 \dots

= \frac{- 171.5 + 29287.82182 \dots}{- 0.45071 \dots}

使用分式法则:

\frac{- a}{- b} = \frac{a}{b}

- 171.5 + 29287.82182 \dots = - (171.5 - 29287.82182 \dots)

= \frac{171.5 - 29287.82182 \dots}{0.45071 \dots}

x = \frac{- 171.5 - 29287.82182 \dots}{2 ( - 0.22535 \dots )} : \frac{171.5 + 29287.82182 \dots}{0.45071 \dots}

\frac{- 171.5 - 29287.82182 \dots}{2 ( - 0.22535 \dots )}

去除括号:

(- a) = - a

= \frac{- 171.5 - 29287.82182 \dots}{- 2 \cdot 0.22535 \dots}

数字相乘:

2 \cdot 0.22535 \dots = 0.45071 \dots

= \frac{- 171.5 - 29287.82182 \dots}{- 0.45071 \dots}

使用分式法则:

\frac{- a}{- b} = \frac{a}{b}

- 171.5 - 29287.82182 \dots = - (171.5 + 29287.82182 \dots)

= \frac{171.5 + 29287.82182 \dots}{0.45071 \dots}

二次方程组的解是:

x = \frac{171.5 - 29287.82182 \dots}{0.45071 \dots}, x = \frac{171.5 + 29287.82182 \dots}{0.45071 \dots}

x = \frac{171.5 - 29287.82182 \dots}{0.45071 \dots}, x = \frac{171.5 + 29287.82182 \dots}{0.45071 \dots}

验证解

找到无定义的点（奇点）:

x = 0

取

\frac{\frac{3.5}{x} - \frac{175}{x}}{1 + \frac{3.5}{x} \cdot \frac{175}{x}}

的分母，令其等于零

x = 0

以下点无定义

x = 0

将不在定义域的点与解相综合:

x = \frac{171.5 - 29287.82182 \dots}{0.45071 \dots}, x = \frac{171.5 + 29287.82182 \dots}{0.45071 \dots}

x = \frac{171.5 - 29287.82182 \dots}{0.45071 \dots}, x = \frac{171.5 + 29287.82182 \dots}{0.45071 \dots}

将解代入原方程进行验证

将它们代入

57. 7^{\circ} + arctan (\frac{3.5}{x}) - arctan (\frac{175}{x}) = 4 5^{\circ}

检验解是否符合

去除与方程不符的解。

检验

\frac{171.5 - 29287.82182 \dots}{0.45071 \dots}

的解:

真

\frac{171.5 - 29287.82182 \dots}{0.45071 \dots}

代入

n = 1

\frac{171.5 - 29287.82182 \dots}{0.45071 \dots}

对于

57. 7^{\circ} + arctan (\frac{3.5}{x}) - arctan (\frac{175}{x}) = 4 5^{\circ}

代入

x = \frac{171.5 - 29287.82182 \dots}{0.45071 \dots}

57. 7^{\circ} + arctan (\frac{3.5}{\frac{171.5 - 29287.82182 \dots}{0.45071 \dots}}) - arctan (\frac{175}{\frac{171.5 - 29287.82182 \dots}{0.45071 \dots}}) = 4 5^{\circ}

整理后得

0.78539 \dots = 0.78539 \dots

\Rightarrow 真

检验

\frac{171.5 + 29287.82182 \dots}{0.45071 \dots}

的解:

真

\frac{171.5 + 29287.82182 \dots}{0.45071 \dots}

代入

n = 1

\frac{171.5 + 29287.82182 \dots}{0.45071 \dots}

对于

57. 7^{\circ} + arctan (\frac{3.5}{x}) - arctan (\frac{175}{x}) = 4 5^{\circ}

代入

x = \frac{171.5 + 29287.82182 \dots}{0.45071 \dots}

57. 7^{\circ} + arctan (\frac{3.5}{\frac{171.5 + 29287.82182 \dots}{0.45071 \dots}}) - arctan (\frac{175}{\frac{171.5 + 29287.82182 \dots}{0.45071 \dots}}) = 4 5^{\circ}

整理后得

0.78539 \dots = 0.78539 \dots

\Rightarrow 真

x = \frac{171.5 - 29287.82182 \dots}{0.45071 \dots}, x = \frac{171.5 + 29287.82182 \dots}{0.45071 \dots}

作图

流行的例子

\frac{1}{2} - cos (\frac{x}{2}) = 0

tan(θ)=(2pi)/3

tan (θ) = \frac{2 π}{3}

2 sin (5 x) = 1

cos (2 x) = - \frac{17}{81}

sin^2(θ)+cos(2θ)=0

sin^{2} (θ) + cos (2 θ) = 0