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受欢迎的三角函数 >

0.08=0.1cos(4x-1.57)

解答

0.08 = 0.1 cos (4 x - 1.57)

解答

x = \frac{1.57}{4} + \frac{πn}{2} + \frac{0.64350 \dots}{4}, x = \frac{π}{2} + \frac{1.57}{4} + \frac{πn}{2} - \frac{0.64350 \dots}{4}

+1

度数

x = 31.70606 \dots^{\circ} + 9 0^{\circ} n, x = 103.27111 \dots^{\circ} + 9 0^{\circ} n

求解步骤

0.08 = 0.1 cos (4 x - 1.57)

交换两边

0.1 cos (4 x - 1.57) = 0.08

在两边乘以

100

0.1 cos (4 x - 1.57) = 0.08

To eliminate decimal points, multiply by 10 for every digit after the decimal pointThere are

2

digits to the right of the decimal point, therefore multiply by

100

0.1 cos (4 x - 1.57) \cdot 100 = 0.08 \cdot 100

整理后得

10 cos (4 x - 1.57) = 8

10 cos (4 x - 1.57) = 8

两边除以

10

10 cos (4 x - 1.57) = 8

两边除以

10

\frac{10 cos ( 4 x - 1.57 )}{10} = \frac{8}{10}

化简

cos (4 x - 1.57) = \frac{4}{5}

cos (4 x - 1.57) = \frac{4}{5}

使用反三角函数性质

cos (4 x - 1.57) = \frac{4}{5}

cos (4 x - 1.57) = \frac{4}{5}

的通解

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

4 x - 1.57 = arccos (\frac{4}{5}) + 2 πn, 4 x - 1.57 = 2 π - arccos (\frac{4}{5}) + 2 πn

4 x - 1.57 = arccos (\frac{4}{5}) + 2 πn, 4 x - 1.57 = 2 π - arccos (\frac{4}{5}) + 2 πn

解

4 x - 1.57 = arccos (\frac{4}{5}) + 2 πn : x = \frac{1.57}{4} + \frac{πn}{2} + \frac{arccos ( \frac{4}{5} )}{4}

4 x - 1.57 = arccos (\frac{4}{5}) + 2 πn

将

1.57

到右边

4 x - 1.57 = arccos (\frac{4}{5}) + 2 πn

两边加上

1.57

4 x - 1.57 + 1.57 = arccos (\frac{4}{5}) + 2 πn + 1.57

化简

4 x = arccos (\frac{4}{5}) + 2 πn + 1.57

4 x = arccos (\frac{4}{5}) + 2 πn + 1.57

两边除以

4

4 x = arccos (\frac{4}{5}) + 2 πn + 1.57

两边除以

4

\frac{4 x}{4} = \frac{arccos ( \frac{4}{5} )}{4} + \frac{2 πn}{4} + \frac{1.57}{4}

化简

\frac{4 x}{4} = \frac{arccos ( \frac{4}{5} )}{4} + \frac{2 πn}{4} + \frac{1.57}{4}

化简

\frac{4 x}{4} : x

\frac{4 x}{4}

数字相除:

\frac{4}{4} = 1

= x

化简

\frac{arccos ( \frac{4}{5} )}{4} + \frac{2 πn}{4} + \frac{1.57}{4} : \frac{1.57}{4} + \frac{πn}{2} + \frac{arccos ( \frac{4}{5} )}{4}

\frac{arccos ( \frac{4}{5} )}{4} + \frac{2 πn}{4} + \frac{1.57}{4}

对同类项分组

= \frac{1.57}{4} + \frac{2 πn}{4} + \frac{arccos ( \frac{4}{5} )}{4}

消掉

\frac{2 πn}{4} : \frac{πn}{2}

\frac{2 πn}{4}

约分:

2

= \frac{πn}{2}

= \frac{1.57}{4} + \frac{πn}{2} + \frac{arccos ( \frac{4}{5} )}{4}

x = \frac{1.57}{4} + \frac{πn}{2} + \frac{arccos ( \frac{4}{5} )}{4}

x = \frac{1.57}{4} + \frac{πn}{2} + \frac{arccos ( \frac{4}{5} )}{4}

x = \frac{1.57}{4} + \frac{πn}{2} + \frac{arccos ( \frac{4}{5} )}{4}

解

4 x - 1.57 = 2 π - arccos (\frac{4}{5}) + 2 πn : x = \frac{π}{2} + \frac{1.57}{4} + \frac{πn}{2} - \frac{arccos ( \frac{4}{5} )}{4}

4 x - 1.57 = 2 π - arccos (\frac{4}{5}) + 2 πn

将

1.57

到右边

4 x - 1.57 = 2 π - arccos (\frac{4}{5}) + 2 πn

两边加上

1.57

4 x - 1.57 + 1.57 = 2 π - arccos (\frac{4}{5}) + 2 πn + 1.57

化简

4 x = 2 π - arccos (\frac{4}{5}) + 2 πn + 1.57

4 x = 2 π - arccos (\frac{4}{5}) + 2 πn + 1.57

两边除以

4

4 x = 2 π - arccos (\frac{4}{5}) + 2 πn + 1.57

两边除以

4

\frac{4 x}{4} = \frac{2 π}{4} - \frac{arccos ( \frac{4}{5} )}{4} + \frac{2 πn}{4} + \frac{1.57}{4}

化简

\frac{4 x}{4} = \frac{2 π}{4} - \frac{arccos ( \frac{4}{5} )}{4} + \frac{2 πn}{4} + \frac{1.57}{4}

化简

\frac{4 x}{4} : x

\frac{4 x}{4}

数字相除:

\frac{4}{4} = 1

= x

化简

\frac{2 π}{4} - \frac{arccos ( \frac{4}{5} )}{4} + \frac{2 πn}{4} + \frac{1.57}{4} : \frac{π}{2} + \frac{1.57}{4} + \frac{πn}{2} - \frac{arccos ( \frac{4}{5} )}{4}

\frac{2 π}{4} - \frac{arccos ( \frac{4}{5} )}{4} + \frac{2 πn}{4} + \frac{1.57}{4}

对同类项分组

= \frac{2 π}{4} + \frac{1.57}{4} + \frac{2 πn}{4} - \frac{arccos ( \frac{4}{5} )}{4}

消掉

\frac{2 π}{4} : \frac{π}{2}

\frac{2 π}{4}

约分:

2

= \frac{π}{2}

= \frac{π}{2} + \frac{1.57}{4} + \frac{2 πn}{4} - \frac{arccos ( \frac{4}{5} )}{4}

消掉

\frac{2 πn}{4} : \frac{πn}{2}

\frac{2 πn}{4}

约分:

2

= \frac{πn}{2}

= \frac{π}{2} + \frac{1.57}{4} + \frac{πn}{2} - \frac{arccos ( \frac{4}{5} )}{4}

x = \frac{π}{2} + \frac{1.57}{4} + \frac{πn}{2} - \frac{arccos ( \frac{4}{5} )}{4}

x = \frac{π}{2} + \frac{1.57}{4} + \frac{πn}{2} - \frac{arccos ( \frac{4}{5} )}{4}

x = \frac{π}{2} + \frac{1.57}{4} + \frac{πn}{2} - \frac{arccos ( \frac{4}{5} )}{4}

x = \frac{1.57}{4} + \frac{πn}{2} + \frac{arccos ( \frac{4}{5} )}{4}, x = \frac{π}{2} + \frac{1.57}{4} + \frac{πn}{2} - \frac{arccos ( \frac{4}{5} )}{4}

以小数形式表示解

x = \frac{1.57}{4} + \frac{πn}{2} + \frac{0.64350 \dots}{4}, x = \frac{π}{2} + \frac{1.57}{4} + \frac{πn}{2} - \frac{0.64350 \dots}{4}

作图

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