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受欢迎的三角函数 >

cos(x)=-1/(5sqrt(2))

解答

cos (x) = - \frac{1}{5 2}

解答

x = 1.71269 \dots + 2 πn, x = - 1.71269 \dots + 2 πn

+1

弧度

x = 1.71269 \dots + 6.28318 \dots n, x = - 1.71269 \dots + 6.28318 \dots n

求解步骤

cos (x) = - \frac{1}{5 2}

化简

- \frac{1}{5 2} : - \frac{2}{10}

- \frac{1}{5 2}

乘以共轭根式

\frac{2}{2}

= - \frac{1 \cdot 2}{5 2 2}

1 \cdot 2 = 2

522 = 10

522

使用根式运算法则:

a a = a

22 = 2

= 5 \cdot 2

数字相乘:

5 \cdot 2 = 10

= 10

= - \frac{2}{10}

cos (x) = - \frac{2}{10}

使用反三角函数性质

cos (x) = - \frac{2}{10}

cos (x) = - \frac{2}{10}

的通解

cos (x) = - a \Rightarrow x = arccos (- a) + 2 πn, x = - arccos (- a) + 2 πn

x = arccos (- \frac{2}{10}) + 2 πn, x = - arccos (- \frac{2}{10}) + 2 πn

x = arccos (- \frac{2}{10}) + 2 πn, x = - arccos (- \frac{2}{10}) + 2 πn

以小数形式表示解

x = 1.71269 \dots + 2 πn, x = - 1.71269 \dots + 2 πn

作图

流行的例子

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