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受欢迎的三角函数 >

3tan^2(x+15)-1=0

解答

3 tan^{2} (x + 1 5^{\circ}) - 1 = 0

解答

x = 18 0^{\circ} n + 1 5^{\circ}, x = 18 0^{\circ} n - 4 5^{\circ}

+1

弧度

x = \frac{π}{12} + πn, x = - \frac{π}{4} + πn

求解步骤

3 tan^{2} (x + 1 5^{\circ}) - 1 = 0

用替代法求解

3 tan^{2} (x + 1 5^{\circ}) - 1 = 0

令

: tan (x + 1 5^{\circ}) = u

3 u^{2} - 1 = 0

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

3 u^{2} - 1 = 0

将

1

到右边

3 u^{2} - 1 = 0

两边加上

1

3 u^{2} - 1 + 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}

u = tan (x + 1 5^{\circ})

代回

tan (x + 1 5^{\circ}) = \frac{1}{3}, tan (x + 1 5^{\circ}) = - \frac{1}{3}

tan (x + 1 5^{\circ}) = \frac{1}{3}, tan (x + 1 5^{\circ}) = - \frac{1}{3}

tan (x + 1 5^{\circ}) = \frac{1}{3} : x = 18 0^{\circ} n + 1 5^{\circ}

tan (x + 1 5^{\circ}) = \frac{1}{3}

使用反三角函数性质

tan (x + 1 5^{\circ}) = \frac{1}{3}

tan (x + 1 5^{\circ}) = \frac{1}{3}

的通解

tan (x) = a \Rightarrow x = arctan (a) + 18 0^{\circ} n

x + 1 5^{\circ} = arctan (\frac{1}{3}) + 18 0^{\circ} n

x + 1 5^{\circ} = arctan (\frac{1}{3}) + 18 0^{\circ} n

解

x + 1 5^{\circ} = arctan (\frac{1}{3}) + 18 0^{\circ} n : x = 18 0^{\circ} n + 1 5^{\circ}

x + 1 5^{\circ} = arctan (\frac{1}{3}) + 18 0^{\circ} n

化简

arctan (\frac{1}{3}) + 18 0^{\circ} n : 3 0^{\circ} + 18 0^{\circ} n

arctan (\frac{1}{3}) + 18 0^{\circ} n

使用以下普通恒等式:

arctan (\frac{1}{3}) = 3 0^{\circ}

x 0 \frac{3}{3} 13 arctan (x) 0 \frac{π}{6} \frac{π}{4} \frac{π}{3} arctan (x) 0^{\circ} 3 0^{\circ} 4 5^{\circ} 6 0^{\circ}

= 3 0^{\circ} + 18 0^{\circ} n

x + 1 5^{\circ} = 3 0^{\circ} + 18 0^{\circ} n

将

1 5^{\circ}

到右边

x + 1 5^{\circ} = 3 0^{\circ} + 18 0^{\circ} n

两边减去

1 5^{\circ}

x + 1 5^{\circ} - 1 5^{\circ} = 3 0^{\circ} + 18 0^{\circ} n - 1 5^{\circ}

化简

x + 1 5^{\circ} - 1 5^{\circ} = 3 0^{\circ} + 18 0^{\circ} n - 1 5^{\circ}

化简

x + 1 5^{\circ} - 1 5^{\circ} : x

x + 1 5^{\circ} - 1 5^{\circ}

同类项相加:

1 5^{\circ} - 1 5^{\circ} = 0

= x

化简

3 0^{\circ} + 18 0^{\circ} n - 1 5^{\circ} : 18 0^{\circ} n + 1 5^{\circ}

3 0^{\circ} + 18 0^{\circ} n - 1 5^{\circ}

对同类项分组

= 18 0^{\circ} n + 3 0^{\circ} - 1 5^{\circ}

6, 12

的最小公倍数:

12

6, 12

最小公倍数 (LCM)

6

质因数分解:

2 \cdot 3

6

6

除以

26 = 3 \cdot 2

= 2 \cdot 3

2, 3

都是质数，因此无法进一步因数分解

= 2 \cdot 3

12

质因数分解:

2 \cdot 2 \cdot 3

12

12

除以

212 = 6 \cdot 2

= 2 \cdot 6

6

除以

26 = 3 \cdot 2

= 2 \cdot 2 \cdot 3

2, 3

都是质数，因此无法进一步因数分解

= 2 \cdot 2 \cdot 3

将每个因子乘以它在

6

或

12

中出现的最多次数

= 2 \cdot 2 \cdot 3

数字相乘:

2 \cdot 2 \cdot 3 = 12

= 12

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

12

对于

3 0^{\circ} :

将分母和分子乘以

2

3 0^{\circ} = \frac{18 0 ^{\circ} 2}{6 \cdot 2} = 3 0^{\circ}

= 3 0^{\circ} - 1 5^{\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} 2 - 18 0 ^{\circ}}{12}

同类项相加:

36 0^{\circ} - 18 0^{\circ} = 18 0^{\circ}

= 18 0^{\circ} n + 1 5^{\circ}

x = 18 0^{\circ} n + 1 5^{\circ}

x = 18 0^{\circ} n + 1 5^{\circ}

x = 18 0^{\circ} n + 1 5^{\circ}

x = 18 0^{\circ} n + 1 5^{\circ}

tan (x + 1 5^{\circ}) = - \frac{1}{3} : x = 18 0^{\circ} n - 4 5^{\circ}

tan (x + 1 5^{\circ}) = - \frac{1}{3}

使用反三角函数性质

tan (x + 1 5^{\circ}) = - \frac{1}{3}

tan (x + 1 5^{\circ}) = - \frac{1}{3}

的通解

tan (x) = - a \Rightarrow x = arctan (- a) + 18 0^{\circ} n

x + 1 5^{\circ} = arctan (- \frac{1}{3}) + 18 0^{\circ} n

x + 1 5^{\circ} = arctan (- \frac{1}{3}) + 18 0^{\circ} n

解

x + 1 5^{\circ} = arctan (- \frac{1}{3}) + 18 0^{\circ} n : x = 18 0^{\circ} n - 4 5^{\circ}

x + 1 5^{\circ} = arctan (- \frac{1}{3}) + 18 0^{\circ} n

化简

arctan (- \frac{1}{3}) + 18 0^{\circ} n : - 3 0^{\circ} + 18 0^{\circ} n

arctan (- \frac{1}{3}) + 18 0^{\circ} n

arctan (- \frac{1}{3}) = - 3 0^{\circ}

arctan (- \frac{1}{3})

利用以下特性:

arctan (- x) = - arctan (x)

arctan (- \frac{1}{3}) = - arctan (\frac{1}{3})

= - arctan (\frac{1}{3})

使用以下普通恒等式:

arctan (\frac{1}{3}) = 3 0^{\circ}

arctan (\frac{1}{3})

x 0 \frac{3}{3} 13 arctan (x) 0 \frac{π}{6} \frac{π}{4} \frac{π}{3} arctan (x) 0^{\circ} 3 0^{\circ} 4 5^{\circ} 6 0^{\circ}

= 3 0^{\circ}

= - 3 0^{\circ}

= - 3 0^{\circ} + 18 0^{\circ} n

x + 1 5^{\circ} = - 3 0^{\circ} + 18 0^{\circ} n

将

1 5^{\circ}

到右边

x + 1 5^{\circ} = - 3 0^{\circ} + 18 0^{\circ} n

两边减去

1 5^{\circ}

x + 1 5^{\circ} - 1 5^{\circ} = - 3 0^{\circ} + 18 0^{\circ} n - 1 5^{\circ}

化简

x + 1 5^{\circ} - 1 5^{\circ} = - 3 0^{\circ} + 18 0^{\circ} n - 1 5^{\circ}

化简

x + 1 5^{\circ} - 1 5^{\circ} : x

x + 1 5^{\circ} - 1 5^{\circ}

同类项相加:

1 5^{\circ} - 1 5^{\circ} = 0

= x

化简

- 3 0^{\circ} + 18 0^{\circ} n - 1 5^{\circ} : 18 0^{\circ} n - 4 5^{\circ}

- 3 0^{\circ} + 18 0^{\circ} n - 1 5^{\circ}

对同类项分组

= 18 0^{\circ} n - 3 0^{\circ} - 1 5^{\circ}

6, 12

的最小公倍数:

12

6, 12

最小公倍数 (LCM)

6

质因数分解:

2 \cdot 3

6

6

除以

26 = 3 \cdot 2

= 2 \cdot 3

2, 3

都是质数，因此无法进一步因数分解

= 2 \cdot 3

12

质因数分解:

2 \cdot 2 \cdot 3

12

12

除以

212 = 6 \cdot 2

= 2 \cdot 6

6

除以

26 = 3 \cdot 2

= 2 \cdot 2 \cdot 3

2, 3

都是质数，因此无法进一步因数分解

= 2 \cdot 2 \cdot 3

将每个因子乘以它在

6

或

12

中出现的最多次数

= 2 \cdot 2 \cdot 3

数字相乘:

2 \cdot 2 \cdot 3 = 12

= 12

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

12

对于

3 0^{\circ} :

将分母和分子乘以

2

3 0^{\circ} = \frac{18 0 ^{\circ} 2}{6 \cdot 2} = 3 0^{\circ}

= - 3 0^{\circ} - 1 5^{\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} 2 - 18 0 ^{\circ}}{12}

同类项相加:

- 36 0^{\circ} - 18 0^{\circ} = - 54 0^{\circ}

= \frac{- 54 0 ^{\circ}}{12}

使用分式法则:

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

= - 4 5^{\circ}

约分:

3

= 18 0^{\circ} n - 4 5^{\circ}

x = 18 0^{\circ} n - 4 5^{\circ}

x = 18 0^{\circ} n - 4 5^{\circ}

x = 18 0^{\circ} n - 4 5^{\circ}

x = 18 0^{\circ} n - 4 5^{\circ}

合并所有解

x = 18 0^{\circ} n + 1 5^{\circ}, x = 18 0^{\circ} n - 4 5^{\circ}

作图

流行的例子

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3 tan^{2} (y) = 5 sec (y) - 1

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