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العربية

受欢迎的三角函数 >

(cos(x)+1/2)<= 0

解答

(cos (x) + \frac{1}{2}) \leq 0

解答

\frac{2 π}{3} + 2 πn \leq x \leq \frac{4 π}{3} + 2 πn

+2

间隔符号

[\frac{2 π}{3} + 2 πn, \frac{4 π}{3} + 2 πn]

十进制

2.09439 \dots + 2 πn \leq x \leq 4.18879 \dots + 2 πn

求解步骤

cos (x) + \frac{1}{2} \leq 0

将

\frac{1}{2}

到右边

cos (x) + \frac{1}{2} \leq 0

两边减去

\frac{1}{2}

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

化简

cos (x) \leq - \frac{1}{2}

cos (x) \leq - \frac{1}{2}

对于

cos (x) \leq a

，若

- 1 < a < 1

，则

arccos (a) + 2 πn \leq x \leq 2 π - arccos (a) + 2 πn

arccos (- \frac{1}{2}) + 2 πn \leq x \leq 2 π - arccos (- \frac{1}{2}) + 2 πn

化简

arccos (- \frac{1}{2}) : \frac{2 π}{3}

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

使用以下普通恒等式:

arccos (- \frac{1}{2}) = \frac{2 π}{3}

x - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2} 0 \frac{1}{2} \frac{2}{2} \frac{3}{2} 1 arccos (x) π \frac{5 π}{6} \frac{3 π}{4} \frac{2 π}{3} \frac{π}{2} \frac{π}{3} \frac{π}{4} \frac{π}{6} 0 arccos (x) 18 0^{\circ} 15 0^{\circ} 13 5^{\circ} 12 0^{\circ} 9 0^{\circ} 6 0^{\circ} 4 5^{\circ} 3 0^{\circ} 0^{\circ}

= \frac{2 π}{3}

化简

2 π - arccos (- \frac{1}{2}) : \frac{4 π}{3}

2 π - arccos (- \frac{1}{2})

使用以下普通恒等式:

arccos (- \frac{1}{2}) = \frac{2 π}{3}

x - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2} 0 \frac{1}{2} \frac{2}{2} \frac{3}{2} 1 arccos (x) π \frac{5 π}{6} \frac{3 π}{4} \frac{2 π}{3} \frac{π}{2} \frac{π}{3} \frac{π}{4} \frac{π}{6} 0 arccos (x) 18 0^{\circ} 15 0^{\circ} 13 5^{\circ} 12 0^{\circ} 9 0^{\circ} 6 0^{\circ} 4 5^{\circ} 3 0^{\circ} 0^{\circ}

= 2 π - \frac{2 π}{3}

化简

2 π - \frac{2 π}{3}

将项转换为分式:

2 π = \frac{2 π 3}{3}

= \frac{2 π 3}{3} - \frac{2 π}{3}

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 π 3 - 2 π}{3}

2 π 3 - 2 π = 4 π

2 π 3 - 2 π

数字相乘:

2 \cdot 3 = 6

= 6 π - 2 π

同类项相加:

6 π - 2 π = 4 π

= 4 π

= \frac{4 π}{3}

= \frac{4 π}{3}

\frac{2 π}{3} + 2 πn \leq x \leq \frac{4 π}{3} + 2 πn

流行的例子

tan(x)>= 1,0<= x<= 2pi

tan (x) \geq 1, 0 \leq x \leq 2 π

1 + sec (x) \geq 0

- sin (x) \leq 0.5

(cos(x))/(1-sin(x))<= 0

\frac{cos ( x )}{1 - sin ( x )} \leq 0

cos^2(x)<(sqrt(2))/2+sin^2(x)

cos^{2} (x) < \frac{2}{2} + sin^{2} (x)