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受欢迎的三角函数 >

3sec^2(x)-4=0,0<= x<2pi

解答

3 sec^{2} (x) - 4 = 0, 0 \leq x < 2 π

解答

x = \frac{π}{6}, x = \frac{11 π}{6}, x = \frac{5 π}{6}, x = \frac{7 π}{6}

+1

度数

x = 3 0^{\circ}, x = 33 0^{\circ}, x = 15 0^{\circ}, x = 21 0^{\circ}

求解步骤

3 sec^{2} (x) - 4 = 0, 0 \leq x < 2 π

用替代法求解

3 sec^{2} (x) - 4 = 0

令

: sec (x) = u

3 u^{2} - 4 = 0

3 u^{2} - 4 = 0 : u = \frac{2 3}{3}, u = - \frac{2 3}{3}

3 u^{2} - 4 = 0

将

4

到右边

3 u^{2} - 4 = 0

两边加上

4

3 u^{2} - 4 + 4 = 0 + 4

化简

3 u^{2} = 4

3 u^{2} = 4

两边除以

3

3 u^{2} = 4

两边除以

3

\frac{3 u ^{2}}{3} = \frac{4}{3}

化简

u^{2} = \frac{4}{3}

u^{2} = \frac{4}{3}

对于

x^{2} = f (a)

解为

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

u = \frac{4}{3}, u = - \frac{4}{3}

\frac{4}{3} = \frac{2 3}{3}

\frac{4}{3}

使用根式运算法则:

假定

a \geq 0, b \geq 0

= \frac{4}{3}

4 = 2

4

因式分解数字:

4 = 2^{2}

= 2^{2}

使用根式运算法则:

2^{2} = 2

= 2

= \frac{2}{3}

\frac{2}{3}

有理化:

\frac{2 3}{3}

\frac{2}{3}

乘以共轭根式

\frac{3}{3}

= \frac{2 3}{3 3}

33 = 3

33

使用根式运算法则:

a a = a

33 = 3

= 3

= \frac{2 3}{3}

= \frac{2 3}{3}

- \frac{4}{3} = - \frac{2 3}{3}

- \frac{4}{3}

化简

\frac{4}{3} : \frac{2}{3}

\frac{4}{3}

使用根式运算法则:

假定

a \geq 0, b \geq 0

= \frac{4}{3}

4 = 2

4

因式分解数字:

4 = 2^{2}

= 2^{2}

使用根式运算法则:

2^{2} = 2

= 2

= \frac{2}{3}

= - \frac{2}{3}

- \frac{2}{3}

有理化:

- \frac{2 3}{3}

- \frac{2}{3}

乘以共轭根式

\frac{3}{3}

= - \frac{2 3}{3 3}

33 = 3

33

使用根式运算法则:

a a = a

33 = 3

= 3

= - \frac{2 3}{3}

= - \frac{2 3}{3}

u = \frac{2 3}{3}, u = - \frac{2 3}{3}

u = sec (x)

代回

sec (x) = \frac{2 3}{3}, sec (x) = - \frac{2 3}{3}

sec (x) = \frac{2 3}{3}, sec (x) = - \frac{2 3}{3}

sec (x) = \frac{2 3}{3}, 0 \leq x < 2 π : x = \frac{π}{6}, x = \frac{11 π}{6}

sec (x) = \frac{2 3}{3}, 0 \leq x < 2 π

sec (x) = \frac{2 3}{3}

的通解

sec (x)

周期表（周期为

2 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} sec (x) 1 \frac{2 3}{3} 22 Undefined - 2 - 2 - \frac{2 3}{3} x π \frac{7 π}{6} \frac{5 π}{4} \frac{4 π}{3} \frac{3 π}{2} \frac{5 π}{3} \frac{7 π}{4} \frac{11 π}{6} sec (x) - 1 - \frac{2 3}{3} - 2 - 2 Undefined 22 \frac{2 3}{3}

x = \frac{π}{6} + 2 πn, x = \frac{11 π}{6} + 2 πn

x = \frac{π}{6} + 2 πn, x = \frac{11 π}{6} + 2 πn

在

0 \leq x < 2 π

范围内的解

x = \frac{π}{6}, x = \frac{11 π}{6}

sec (x) = - \frac{2 3}{3}, 0 \leq x < 2 π : x = \frac{5 π}{6}, x = \frac{7 π}{6}

sec (x) = - \frac{2 3}{3}, 0 \leq x < 2 π

sec (x) = - \frac{2 3}{3}

的通解

sec (x)

周期表（周期为

2 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} sec (x) 1 \frac{2 3}{3} 22 Undefined - 2 - 2 - \frac{2 3}{3} x π \frac{7 π}{6} \frac{5 π}{4} \frac{4 π}{3} \frac{3 π}{2} \frac{5 π}{3} \frac{7 π}{4} \frac{11 π}{6} sec (x) - 1 - \frac{2 3}{3} - 2 - 2 Undefined 22 \frac{2 3}{3}

x = \frac{5 π}{6} + 2 πn, x = \frac{7 π}{6} + 2 πn

x = \frac{5 π}{6} + 2 πn, x = \frac{7 π}{6} + 2 πn

在

0 \leq x < 2 π

范围内的解

x = \frac{5 π}{6}, x = \frac{7 π}{6}

合并所有解

x = \frac{π}{6}, x = \frac{11 π}{6}, x = \frac{5 π}{6}, x = \frac{7 π}{6}

作图

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