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 >

tan(x)=2+tan(3x)

解答

tan (x) = 2 + tan (3 x)

解答

x = \frac{π}{4} + πn, x = 1.17809 \dots + πn, x = - 0.39269 \dots + πn

+1

度数

x = 4 5^{\circ} + 18 0^{\circ} n, x = 67. 5^{\circ} + 18 0^{\circ} n, x = - 22. 5^{\circ} + 18 0^{\circ} n

求解步骤

tan (x) = 2 + tan (3 x)

两边减去

2 + tan (3 x)

tan (x) - 2 - tan (3 x) = 0

使用三角恒等式改写

- 2 - tan (3 x) + tan (x)

tan (3 x) = \frac{3 tan ( x ) - tan ^{3} ( x )}{1 - 3 tan ^{2} ( x )}

tan (3 x)

使用三角恒等式改写

tan (3 x)

改写为

= tan (2 x + x)

使用角和恒等式:

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

= \frac{tan ( 2 x ) + tan ( x )}{1 - tan ( 2 x ) tan ( x )}

= \frac{tan ( 2 x ) + tan ( x )}{1 - tan ( 2 x ) tan ( x )}

使用倍角公式:

tan (2 x) = \frac{2 tan ( x )}{1 - tan ^{2} ( x )}

= \frac{\frac{2 t a n ( x )}{1 - t a n ^{2} ( x )} + tan ( x )}{1 - \frac{2 t a n ( x )}{1 - t a n ^{2} ( x )} tan ( x )}

化简

\frac{\frac{2 t a n ( x )}{1 - t a n ^{2} ( x )} + tan ( x )}{1 - \frac{2 t a n ( x )}{1 - t a n ^{2} ( x )} tan ( x )} : \frac{3 tan ( x ) - tan ^{3} ( x )}{1 - 3 tan ^{2} ( x )}

\frac{\frac{2 t a n ( x )}{1 - t a n ^{2} ( x )} + tan ( x )}{1 - \frac{2 t a n ( x )}{1 - t a n ^{2} ( x )} tan ( x )}

\frac{2 tan ( x )}{1 - tan ^{2} ( x )} tan (x) = \frac{2 tan ^{2} ( x )}{1 - tan ^{2} ( x )}

\frac{2 tan ( x )}{1 - tan ^{2} ( x )} tan (x)

分式相乘:

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

= \frac{2 tan ( x ) tan ( x )}{1 - tan ^{2} ( x )}

2 tan (x) tan (x) = 2 tan^{2} (x)

2 tan (x) tan (x)

使用指数法则:

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

tan (x) tan (x) = tan^{1 + 1} (x)

= 2 tan^{1 + 1} (x)

数字相加:

1 + 1 = 2

= 2 tan^{2} (x)

= \frac{2 tan ^{2} ( x )}{1 - tan ^{2} ( x )}

= \frac{\frac{2 t a n ( x )}{- t a n ^{2} ( x ) + 1} + tan ( x )}{1 - \frac{2 t a n ^{2} ( x )}{- t a n ^{2} ( x ) + 1}}

化简

\frac{2 tan ( x )}{1 - tan ^{2} ( x )} + tan (x) : \frac{3 tan ( x ) - tan ^{3} ( x )}{1 - tan ^{2} ( x )}

\frac{2 tan ( x )}{1 - tan ^{2} ( x )} + tan (x)

将项转换为分式:

tan (x) = \frac{tan ( x ) ( 1 - tan ^{2} ( x ) )}{1 - tan ^{2} ( x )}

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

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{2 tan ( x ) + tan ( x ) ( 1 - tan ^{2} ( x ) )}{1 - tan ^{2} ( x )}

乘开

2 tan (x) + tan (x) (1 - tan^{2} (x)) : 3 tan (x) - tan^{3} (x)

2 tan (x) + tan (x) (1 - tan^{2} (x))

乘开

tan (x) (1 - tan^{2} (x)) : tan (x) - tan^{3} (x)

tan (x) (1 - tan^{2} (x))

使用分配律:

a (b - c) = ab - a c

a = tan (x), b = 1, c = tan^{2} (x)

= tan (x) 1 - tan (x) tan^{2} (x)

= 1 tan (x) - tan^{2} (x) tan (x)

化简

1 \cdot tan (x) - tan^{2} (x) tan (x) : tan (x) - tan^{3} (x)

1 tan (x) - tan^{2} (x) tan (x)

1 \cdot tan (x) = tan (x)

1 tan (x)

乘以:

1 \cdot tan (x) = tan (x)

= tan (x)

tan^{2} (x) tan (x) = tan^{3} (x)

tan^{2} (x) tan (x)

使用指数法则:

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

tan^{2} (x) tan (x) = tan^{2 + 1} (x)

= tan^{2 + 1} (x)

数字相加:

2 + 1 = 3

= tan^{3} (x)

= tan (x) - tan^{3} (x)

= tan (x) - tan^{3} (x)

= 2 tan (x) + tan (x) - tan^{3} (x)

同类项相加:

2 tan (x) + tan (x) = 3 tan (x)

= 3 tan (x) - tan^{3} (x)

= \frac{3 tan ( x ) - tan ^{3} ( x )}{1 - tan ^{2} ( x )}

= \frac{\frac{3 t a n ( x ) - t a n ^{3} ( x )}{1 - t a n ^{2} ( x )}}{1 - \frac{2 t a n ^{2} ( x )}{- t a n ^{2} ( x ) + 1}}

使用分式法则:

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

= \frac{3 tan ( x ) - tan ^{3} ( x )}{( 1 - tan ^{2} ( x ) ) ( 1 - \frac{2 t a n ^{2} ( x )}{1 - t a n ^{2} ( x )} )}

化简

1 - \frac{2 tan ^{2} ( x )}{1 - tan ^{2} ( x )} : \frac{1 - 3 tan ^{2} ( x )}{1 - tan ^{2} ( x )}

1 - \frac{2 tan ^{2} ( x )}{1 - tan ^{2} ( x )}

将项转换为分式:

1 = \frac{1 ( 1 - tan ^{2} ( x ) )}{1 - tan ^{2} ( x )}

= \frac{1 ( 1 - tan ^{2} ( x ) )}{1 - tan ^{2} ( x )} - \frac{2 tan ^{2} ( x )}{1 - tan ^{2} ( x )}

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 ( 1 - tan ^{2} ( x ) ) - 2 tan ^{2} ( x )}{1 - tan ^{2} ( x )}

1 \cdot (1 - tan^{2} (x)) - 2 tan^{2} (x) = 1 - 3 tan^{2} (x)

1 (1 - tan^{2} (x)) - 2 tan^{2} (x)

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

1 (1 - tan^{2} (x))

乘以:

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

= 1 - tan^{2} (x)

去除括号:

(a) = a

= 1 - tan^{2} (x)

= 1 - tan^{2} (x) - 2 tan^{2} (x)

同类项相加:

- tan^{2} (x) - 2 tan^{2} (x) = - 3 tan^{2} (x)

= 1 - 3 tan^{2} (x)

= \frac{1 - 3 tan ^{2} ( x )}{1 - tan ^{2} ( x )}

= \frac{3 tan ( x ) - tan ^{3} ( x )}{\frac{- 3 t a n ^{2} ( x ) + 1}{- t a n ^{2} ( x ) + 1} ( - tan ^{2} ( x ) + 1 )}

乘

(1 - tan^{2} (x)) \frac{1 - 3 tan ^{2} ( x )}{1 - tan ^{2} ( x )} : 1 - 3 tan^{2} (x)

(1 - tan^{2} (x)) \frac{1 - 3 tan ^{2} ( x )}{1 - tan ^{2} ( x )}

分式相乘:

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

= \frac{( 1 - 3 tan ^{2} ( x ) ) ( 1 - tan ^{2} ( x ) )}{1 - tan ^{2} ( x )}

约分:

1 - tan^{2} (x)

= 1 - 3 tan^{2} (x)

= \frac{3 tan ( x ) - tan ^{3} ( x )}{1 - 3 tan ^{2} ( x )}

= \frac{3 tan ( x ) - tan ^{3} ( x )}{1 - 3 tan ^{2} ( x )}

= - 2 - \frac{3 tan ( x ) - tan ^{3} ( x )}{1 - 3 tan ^{2} ( x )} + tan (x)

合并分式

- \frac{3 tan ( x ) - tan ^{3} ( x )}{- 3 tan ^{2} ( x ) + 1} + tan (x) : \frac{- 2 tan ( x ) - 2 tan ^{3} ( x )}{1 - 3 tan ^{2} ( x )}

- \frac{3 tan ( x ) - tan ^{3} ( x )}{- 3 tan ^{2} ( x ) + 1} + tan (x)

将项转换为分式:

tan (x) = \frac{tan ( x ) ( 1 - 3 tan ^{2} ( x ) )}{1 - 3 tan ^{2} ( x )}

= - \frac{3 tan ( x ) - tan ^{3} ( x )}{1 - 3 tan ^{2} ( x )} + \frac{tan ( x ) ( 1 - 3 tan ^{2} ( x ) )}{1 - 3 tan ^{2} ( x )}

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{- ( 3 tan ( x ) - tan ^{3} ( x ) ) + tan ( x ) ( 1 - 3 tan ^{2} ( x ) )}{1 - 3 tan ^{2} ( x )}

乘开

- (3 tan (x) - tan^{3} (x)) + tan (x) (1 - 3 tan^{2} (x)) : - 2 tan (x) - 2 tan^{3} (x)

- (3 tan (x) - tan^{3} (x)) + tan (x) (1 - 3 tan^{2} (x))

- (3 tan (x) - tan^{3} (x)) : - 3 tan (x) + tan^{3} (x)

- (3 tan (x) - tan^{3} (x))

打开括号

= - (3 tan (x)) - (- tan^{3} (x))

使用加减运算法则

- (- a) = a, - (a) = - a

= - 3 tan (x) + tan^{3} (x)

= - 3 tan (x) + tan^{3} (x) + tan (x) (1 - 3 tan^{2} (x))

乘开

tan (x) (1 - 3 tan^{2} (x)) : tan (x) - 3 tan^{3} (x)

tan (x) (1 - 3 tan^{2} (x))

使用分配律:

a (b - c) = ab - a c

a = tan (x), b = 1, c = 3 tan^{2} (x)

= tan (x) \cdot 1 - tan (x) \cdot 3 tan^{2} (x)

= 1 \cdot tan (x) - 3 tan^{2} (x) tan (x)

化简

1 \cdot tan (x) - 3 tan^{2} (x) tan (x) : tan (x) - 3 tan^{3} (x)

1 \cdot tan (x) - 3 tan^{2} (x) tan (x)

1 \cdot tan (x) = tan (x)

1 \cdot tan (x)

乘以:

1 \cdot tan (x) = tan (x)

= tan (x)

3 tan^{2} (x) tan (x) = 3 tan^{3} (x)

3 tan^{2} (x) tan (x)

使用指数法则:

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

tan^{2} (x) tan (x) = tan^{2 + 1} (x)

= 3 tan^{2 + 1} (x)

数字相加:

2 + 1 = 3

= 3 tan^{3} (x)

= tan (x) - 3 tan^{3} (x)

= tan (x) - 3 tan^{3} (x)

= - 3 tan (x) + tan^{3} (x) + tan (x) - 3 tan^{3} (x)

化简

- 3 tan (x) + tan^{3} (x) + tan (x) - 3 tan^{3} (x) : - 2 tan (x) - 2 tan^{3} (x)

- 3 tan (x) + tan^{3} (x) + tan (x) - 3 tan^{3} (x)

同类项相加:

tan^{3} (x) - 3 tan^{3} (x) = - 2 tan^{3} (x)

= - 3 tan (x) - 2 tan^{3} (x) + tan (x)

同类项相加:

- 3 tan (x) + tan (x) = - 2 tan (x)

= - 2 tan (x) - 2 tan^{3} (x)

= - 2 tan (x) - 2 tan^{3} (x)

= \frac{- 2 tan ( x ) - 2 tan ^{3} ( x )}{1 - 3 tan ^{2} ( x )}

= \frac{- 2 tan ( x ) - 2 tan ^{3} ( x )}{1 - 3 tan ^{2} ( x )} - 2

- 2 + \frac{- 2 tan ( x ) - 2 tan ^{3} ( x )}{1 - 3 tan ^{2} ( x )} = 0

- 2 + \frac{- 2 tan ( x ) - 2 tan ^{3} ( x )}{1 - 3 tan ^{2} ( x )} = 0

用替代法求解

- 2 + \frac{- 2 tan ( x ) - 2 tan ^{3} ( x )}{1 - 3 tan ^{2} ( x )} = 0

令

: tan (x) = u

- 2 + \frac{- 2 u - 2 u ^{3}}{1 - 3 u ^{2}} = 0

- 2 + \frac{- 2 u - 2 u ^{3}}{1 - 3 u ^{2}} = 0 : u = 1, u = 1 + 2, u = 1 - 2

- 2 + \frac{- 2 u - 2 u ^{3}}{1 - 3 u ^{2}} = 0

在两边乘以

1 - 3 u^{2}

- 2 + \frac{- 2 u - 2 u ^{3}}{1 - 3 u ^{2}} = 0

在两边乘以

1 - 3 u^{2}

- 2 (1 - 3 u^{2}) + \frac{- 2 u - 2 u ^{3}}{1 - 3 u ^{2}} (1 - 3 u^{2}) = 0 \cdot (1 - 3 u^{2})

化简

- 2 (1 - 3 u^{2}) + \frac{- 2 u - 2 u ^{3}}{1 - 3 u ^{2}} (1 - 3 u^{2}) = 0 \cdot (1 - 3 u^{2})

化简

\frac{- 2 u - 2 u ^{3}}{1 - 3 u ^{2}} (1 - 3 u^{2}) : - 2 u - 2 u^{3}

\frac{- 2 u - 2 u ^{3}}{1 - 3 u ^{2}} (1 - 3 u^{2})

分式相乘:

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

= \frac{( - 2 u - 2 u ^{3} ) ( 1 - 3 u ^{2} )}{1 - 3 u ^{2}}

约分:

1 - 3 u^{2}

= - - 2 u - 2 u^{3}

化简

0 \cdot (1 - 3 u^{2}) : 0

0 \cdot (1 - 3 u^{2})

使用法则

0 \cdot a = 0

= 0

- 2 (1 - 3 u^{2}) - 2 u - 2 u^{3} = 0

- 2 (1 - 3 u^{2}) - 2 u - 2 u^{3} = 0

- 2 (1 - 3 u^{2}) - 2 u - 2 u^{3} = 0

解

- 2 (1 - 3 u^{2}) - 2 u - 2 u^{3} = 0 : u = 1, u = 1 + 2, u = 1 - 2

- 2 (1 - 3 u^{2}) - 2 u - 2 u^{3} = 0

因式分解

- 2 (1 - 3 u^{2}) - 2 u - 2 u^{3} : - 2 (u - 1) (u^{2} - 2 u - 1)

- 2 (1 - 3 u^{2}) - 2 u - 2 u^{3}

因式分解出通项

2

= - 2 (1 - u^{2} \cdot 3 + u + u^{3})

分解

u^{3} - 3 u^{2} + u + 1 : (u - 1) (u^{2} - 2 u - 1)

1 - u^{2} \cdot 3 + u + u^{3}

使用有理根定理

a_{0} = 1, a_{n} = 1

a_{0}

的除数

: 1, a_{n}

的除数

: 1

因此，检验以下有理数:

\pm \frac{1}{1}

\frac{1}{1}

是表达式的根，所以因式分解

u - 1

= (u - 1) \frac{u ^{3} - 3 u ^{2} + u + 1}{u - 1}

\frac{u ^{3} - 3 u ^{2} + u + 1}{u - 1} = u^{2} - 2 u - 1

\frac{u ^{3} - 3 u ^{2} + u + 1}{u - 1}

对

\frac{u ^{3} - 3 u ^{2} + u + 1}{u - 1}

做除法:

\frac{u ^{3} - 3 u ^{2} + u + 1}{u - 1} = u^{2} + \frac{- 2 u ^{2} + u + 1}{u - 1}

将分子

u^{3} - 3 u^{2} + u + 1

与除数

u - 1

的首项系数相除：

\frac{u ^{3}}{u} = u^{2}

商 = u^{2}

将

u - 1

乘以

u^{2} : u^{3} - u^{2}

将

u^{3} - 3 u^{2} + u + 1

减去

u^{3} - u^{2}

得到新的余数

余数 = - 2 u^{2} + u + 1

因此

\frac{u ^{3} - 3 u ^{2} + u + 1}{u - 1} = u^{2} + \frac{- 2 u ^{2} + u + 1}{u - 1}

= u^{2} + \frac{- 2 u ^{2} + u + 1}{u - 1}

对

\frac{- 2 u ^{2} + u + 1}{u - 1}

做除法:

\frac{- 2 u ^{2} + u + 1}{u - 1} = - 2 u + \frac{- u + 1}{u - 1}

将分子

- 2 u^{2} + u + 1

与除数

u - 1

的首项系数相除：

\frac{- 2 u ^{2}}{u} = - 2 u

商 = - 2 u

将

u - 1

乘以

- 2 u : - 2 u^{2} + 2 u

将

- 2 u^{2} + u + 1

减去

- 2 u^{2} + 2 u

得到新的余数

余数 = - u + 1

因此

\frac{- 2 u ^{2} + u + 1}{u - 1} = - 2 u + \frac{- u + 1}{u - 1}

= u^{2} - 2 u + \frac{- u + 1}{u - 1}

对

\frac{- u + 1}{u - 1}

做除法:

\frac{- u + 1}{u - 1} = - 1

将分子

- u + 1

与除数

u - 1

的首项系数相除：

\frac{- u}{u} = - 1

商 = - 1

将

u - 1

乘以

- 1 : - u + 1

将

- u + 1

减去

- u + 1

得到新的余数

余数 = 0

因此

\frac{- u + 1}{u - 1} = - 1

= u^{2} - 2 u - 1

= (u - 1) (u^{2} - 2 u - 1)

= - 2 (u - 1) (u^{2} - 2 u - 1)

- 2 (u - 1) (u^{2} - 2 u - 1) = 0

使用零因数法则： If

ab = 0

then

a = 0

or

b = 0

u - 1 = 0 or u^{2} - 2 u - 1 = 0

解

u - 1 = 0 : u = 1

u - 1 = 0

将

1

到右边

u - 1 = 0

两边加上

1

u - 1 + 1 = 0 + 1

化简

u = 1

u = 1

解

u^{2} - 2 u - 1 = 0 : u = 1 + 2, u = 1 - 2

u^{2} - 2 u - 1 = 0

使用求根公式求解

u^{2} - 2 u - 1 = 0

二次方程求根公式:

若

a = 1, b = - 2, c = - 1

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

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

(- 2)^{2} - 4 \cdot 1 \cdot (- 1) = 22

(- 2)^{2} - 4 \cdot 1 \cdot (- 1)

使用法则

- (- a) = a

= (- 2)^{2} + 4 \cdot 1 \cdot 1

使用指数法则:

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

若

n

是偶数

(- 2)^{2} = 2^{2}

= 2^{2} + 4 \cdot 1 \cdot 1

数字相乘:

4 \cdot 1 \cdot 1 = 4

= 2^{2} + 4

2^{2} = 4

= 4 + 4

数字相加:

4 + 4 = 8

= 8

8

质因数分解:

2^{3}

8

8

除以

28 = 4 \cdot 2

= 2 \cdot 4

4

除以

24 = 2 \cdot 2

= 2 \cdot 2 \cdot 2

2

是质数，因此无法进一步因数分解

= 2 \cdot 2 \cdot 2

= 2^{3}

= 2^{3}

使用指数法则:

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

= 2^{2} \cdot 2

使用根式运算法则:

n ab = n a n b

= 2 2^{2}

使用根式运算法则:

n a^{n} = a

2^{2} = 2

= 22

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

将解分隔开

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

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

\frac{- ( - 2 ) + 2 2}{2 \cdot 1}

使用法则

- (- a) = a

= \frac{2 + 2 2}{2 \cdot 1}

数字相乘:

2 \cdot 1 = 2

= \frac{2 + 2 2}{2}

分解

2 + 22 : 2 (1 + 2)

2 + 22

改写为

= 2 \cdot 1 + 22

因式分解出通项

2

= 2 (1 + 2)

= \frac{2 ( 1 + 2 )}{2}

数字相除:

\frac{2}{2} = 1

= 1 + 2

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

\frac{- ( - 2 ) - 2 2}{2 \cdot 1}

使用法则

- (- a) = a

= \frac{2 - 2 2}{2 \cdot 1}

数字相乘:

2 \cdot 1 = 2

= \frac{2 - 2 2}{2}

分解

2 - 22 : 2 (1 - 2)

2 - 22

改写为

= 2 \cdot 1 - 22

因式分解出通项

2

= 2 (1 - 2)

= \frac{2 ( 1 - 2 )}{2}

数字相除:

\frac{2}{2} = 1

= 1 - 2

二次方程组的解是:

u = 1 + 2, u = 1 - 2

解为

u = 1, u = 1 + 2, u = 1 - 2

u = 1, u = 1 + 2, u = 1 - 2

验证解

找到无定义的点（奇点）:

u = \frac{1}{3}, u = - \frac{1}{3}

取

- 2 + \frac{- 2 u - 2 u ^{3}}{1 - 3 u ^{2}}

的分母，令其等于零

解

1 - 3 u^{2} = 0 : u = \frac{1}{3}, u = - \frac{1}{3}

1 - 3 u^{2} = 0

将

1

到右边

1 - 3 u^{2} = 0

两边减去

1

1 - 3 u^{2} - 1 = 0 - 1

化简

- 3 u^{2} = - 1

- 3 u^{2} = - 1

两边除以

- 3

- 3 u^{2} = - 1

两边除以

- 3

\frac{- 3 u ^{2}}{- 3} = \frac{- 1}{- 3}

化简

u^{2} = \frac{1}{3}

u^{2} = \frac{1}{3}

对于

x^{2} = f (a)

解为

x = f (a), - f (a)

u = \frac{1}{3}, u = - \frac{1}{3}

\frac{1}{3} = \frac{1}{3}

\frac{1}{3}

使用根式运算法则:

\frac{a}{b} = \frac{a}{b}, a \geq 0, b \geq 0

= \frac{1}{3}

使用根式运算法则:

1 = 1

1 = 1

= \frac{1}{3}

- \frac{1}{3} = - \frac{1}{3}

- \frac{1}{3}

使用根式运算法则:

\frac{a}{b} = \frac{a}{b}, a \geq 0, b \geq 0

= - \frac{1}{3}

使用根式运算法则:

1 = 1

1 = 1

= - \frac{1}{3}

u = \frac{1}{3}, u = - \frac{1}{3}

以下点无定义

u = \frac{1}{3}, u = - \frac{1}{3}

将不在定义域的点与解相综合:

u = 1, u = 1 + 2, u = 1 - 2

u = tan (x)

代回

tan (x) = 1, tan (x) = 1 + 2, tan (x) = 1 - 2

tan (x) = 1, tan (x) = 1 + 2, tan (x) = 1 - 2

tan (x) = 1 : x = \frac{π}{4} + πn

tan (x) = 1

tan (x) = 1

的通解

tan (x)

周期表（周期为

πn

）：

x 0 \frac{π}{6} \frac{π}{4} \frac{π}{3} \frac{π}{2} \frac{2 π}{3} \frac{3 π}{4} \frac{5 π}{6} tan (x) 0 \frac{3}{3} 13 \pm \infty - 3 - 1 - \frac{3}{3}

x = \frac{π}{4} + πn

x = \frac{π}{4} + πn

tan (x) = 1 + 2 : x = arctan (1 + 2) + πn

tan (x) = 1 + 2

使用反三角函数性质

tan (x) = 1 + 2

tan (x) = 1 + 2

的通解

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

x = arctan (1 + 2) + πn

x = arctan (1 + 2) + πn

tan (x) = 1 - 2 : x = arctan (1 - 2) + πn

tan (x) = 1 - 2

使用反三角函数性质

tan (x) = 1 - 2

tan (x) = 1 - 2

的通解

tan (x) = - a \Rightarrow x = arctan (- a) + πn

x = arctan (1 - 2) + πn

x = arctan (1 - 2) + πn

合并所有解

x = \frac{π}{4} + πn, x = arctan (1 + 2) + πn, x = arctan (1 - 2) + πn

以小数形式表示解

x = \frac{π}{4} + πn, x = 1.17809 \dots + πn, x = - 0.39269 \dots + πn

作图

流行的例子

2 sin (x) - 3 = 0

sin^2(x)=2sin^2(x/2)

sin^{2} (x) = 2 sin^{2} (\frac{x}{2})

5sin(x)=cos(x)-4

5 sin (x) = cos (x) - 4

-21tan(x)+3sqrt(3)=-3(sqrt(3)+tan(x))

- 21 tan (x) + 33 = - 3 (3 + tan (x))

tan (y) = - 1