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受欢迎的三角函数 >

sec(255)

解答

sec (25 5^{\circ})

解答

- 2 - 6

+1

十进制

- 3.86370 \dots

求解步骤

sec (25 5^{\circ})

使用三角恒等式改写:

\frac{1}{cos ( 25 5 ^{\circ} )}

sec (25 5^{\circ})

使用基本三角恒等式:

sec (x) = \frac{1}{cos ( x )}

= \frac{1}{cos ( 25 5 ^{\circ} )}

= \frac{1}{cos ( 25 5 ^{\circ} )}

使用三角恒等式改写:

cos (25 5^{\circ}) = \frac{2 - 6}{4}

cos (25 5^{\circ})

使用三角恒等式改写:

cos (13 5^{\circ}) cos (12 0^{\circ}) - sin (13 5^{\circ}) sin (12 0^{\circ})

cos (25 5^{\circ})

将

cos (25 5^{\circ})

写为

cos (13 5^{\circ} + 12 0^{\circ})

= cos (13 5^{\circ} + 12 0^{\circ})

使用角和恒等式:

cos (s + t) = cos (s) cos (t) - sin (s) sin (t)

= cos (13 5^{\circ}) cos (12 0^{\circ}) - sin (13 5^{\circ}) sin (12 0^{\circ})

= cos (13 5^{\circ}) cos (12 0^{\circ}) - sin (13 5^{\circ}) sin (12 0^{\circ})

使用以下普通恒等式:

cos (13 5^{\circ}) = - \frac{2}{2}

cos (13 5^{\circ})

cos (x)

周期表（周期为

36 0^{\circ} n

）：

x 0 3 0^{\circ} 4 5^{\circ} 6 0^{\circ} 9 0^{\circ} 12 0^{\circ} 13 5^{\circ} 15 0^{\circ} cos (x) 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} x 18 0^{\circ} 21 0^{\circ} 22 5^{\circ} 24 0^{\circ} 27 0^{\circ} 30 0^{\circ} 31 5^{\circ} 33 0^{\circ} cos (x) - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2} 0 \frac{1}{2} \frac{2}{2} \frac{3}{2}

= - \frac{2}{2}

使用以下普通恒等式:

cos (12 0^{\circ}) = - \frac{1}{2}

cos (12 0^{\circ})

cos (x)

周期表（周期为

36 0^{\circ} n

）：

x 0 3 0^{\circ} 4 5^{\circ} 6 0^{\circ} 9 0^{\circ} 12 0^{\circ} 13 5^{\circ} 15 0^{\circ} cos (x) 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} x 18 0^{\circ} 21 0^{\circ} 22 5^{\circ} 24 0^{\circ} 27 0^{\circ} 30 0^{\circ} 31 5^{\circ} 33 0^{\circ} cos (x) - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2} 0 \frac{1}{2} \frac{2}{2} \frac{3}{2}

= - \frac{1}{2}

使用以下普通恒等式:

sin (13 5^{\circ}) = \frac{2}{2}

sin (13 5^{\circ})

sin (x)

周期表（周期为

36 0^{\circ} n

"）：

x 0 3 0^{\circ} 4 5^{\circ} 6 0^{\circ} 9 0^{\circ} 12 0^{\circ} 13 5^{\circ} 15 0^{\circ} sin (x) 0 \frac{1}{2} \frac{2}{2} \frac{3}{2} 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} x 18 0^{\circ} 21 0^{\circ} 22 5^{\circ} 24 0^{\circ} 27 0^{\circ} 30 0^{\circ} 31 5^{\circ} 33 0^{\circ} sin (x) 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2}

= \frac{2}{2}

使用以下普通恒等式:

sin (12 0^{\circ}) = \frac{3}{2}

sin (12 0^{\circ})

sin (x)

周期表（周期为

36 0^{\circ} n

"）：

x 0 3 0^{\circ} 4 5^{\circ} 6 0^{\circ} 9 0^{\circ} 12 0^{\circ} 13 5^{\circ} 15 0^{\circ} sin (x) 0 \frac{1}{2} \frac{2}{2} \frac{3}{2} 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} x 18 0^{\circ} 21 0^{\circ} 22 5^{\circ} 24 0^{\circ} 27 0^{\circ} 30 0^{\circ} 31 5^{\circ} 33 0^{\circ} sin (x) 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2}

= \frac{3}{2}

= (- \frac{2}{2}) (- \frac{1}{2}) - \frac{2}{2} \cdot \frac{3}{2}

化简

(- \frac{2}{2}) (- \frac{1}{2}) - \frac{2}{2} \cdot \frac{3}{2} : \frac{2 - 6}{4}

(- \frac{2}{2}) (- \frac{1}{2}) - \frac{2}{2} \cdot \frac{3}{2}

去除括号:

(- a) = - a, - (- a) = a

= \frac{2}{2} \cdot \frac{1}{2} - \frac{2}{2} \cdot \frac{3}{2}

\frac{2}{2} \cdot \frac{1}{2} = \frac{2}{4}

\frac{2}{2} \cdot \frac{1}{2}

分式相乘:

\frac{a}{b} \cdot \frac{c}{d} = \frac{a \cdot c}{b \cdot d}

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

乘以:

2 \cdot 1 = 2

= \frac{2}{2 \cdot 2}

数字相乘:

2 \cdot 2 = 4

= \frac{2}{4}

\frac{2}{2} \cdot \frac{3}{2} = \frac{6}{4}

\frac{2}{2} \cdot \frac{3}{2}

分式相乘:

\frac{a}{b} \cdot \frac{c}{d} = \frac{a \cdot c}{b \cdot d}

= \frac{2 3}{2 \cdot 2}

数字相乘:

2 \cdot 2 = 4

= \frac{2 3}{4}

化简

23 : 6

23

使用根式运算法则:

a b = a \cdot b

23 = 2 \cdot 3

= 2 \cdot 3

数字相乘:

2 \cdot 3 = 6

= 6

= \frac{6}{4}

= \frac{2}{4} - \frac{6}{4}

使用法则

\frac{a}{c} \pm \frac{b}{c} = \frac{a \pm b}{c}

= \frac{2 - 6}{4}

= \frac{2 - 6}{4}

= \frac{1}{\frac{2 - 6}{4}}

化简

\frac{1}{\frac{2 - 6}{4}} : - 2 - 6

\frac{1}{\frac{2 - 6}{4}}

使用分式法则:

\frac{1}{\frac{b}{c}} = \frac{c}{b}

= \frac{4}{2 - 6}

\frac{4}{2 - 6}

有理化:

- 2 - 6

\frac{4}{2 - 6}

乘以共轭根式

\frac{2 + 6}{2 + 6}

= \frac{4 ( 2 + 6 )}{( 2 - 6 ) ( 2 + 6 )}

(2 - 6) (2 + 6) = - 4

(2 - 6) (2 + 6)

使用平方差公式:

(a - b) (a + b) = a^{2} - b^{2}

a = 2, b = 6

= (2)^{2} - (6)^{2}

化简

(2)^{2} - (6)^{2} : - 4

(2)^{2} - (6)^{2}

(2)^{2} = 2

(2)^{2}

使用根式运算法则:

a = a^{\frac{1}{2}}

= (2^{\frac{1}{2}})^{2}

使用指数法则:

(a^{b})^{c} = a^{b c}

= 2^{\frac{1}{2} \cdot 2}

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

\frac{1}{2} \cdot 2

分式相乘:

a \cdot \frac{b}{c} = \frac{a \cdot b}{c}

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

约分:

2

= 1

= 2

(6)^{2} = 6

(6)^{2}

使用根式运算法则:

a = a^{\frac{1}{2}}

= (6^{\frac{1}{2}})^{2}

使用指数法则:

(a^{b})^{c} = a^{b c}

= 6^{\frac{1}{2} \cdot 2}

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

\frac{1}{2} \cdot 2

分式相乘:

a \cdot \frac{b}{c} = \frac{a \cdot b}{c}

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

约分:

2

= 1

= 6

= 2 - 6

数字相减:

2 - 6 = - 4

= - 4

= - 4

= \frac{4 ( 2 + 6 )}{- 4}

使用分式法则:

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

= - \frac{4 ( 2 + 6 )}{4}

数字相除:

\frac{4}{4} = 1

= - (2 + 6)

打开括号

= - (2) - (6)

使用加减运算法则

+ (- a) = - a

= - 2 - 6

= - 2 - 6

= - 2 - 6

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arcsec(5+sqrt(3))

arcsec (5 + 3)

- 5 sin (\frac{π}{6})

sin(600)+sec(660)-cot(690)

sin (60 0^{\circ}) + sec (66 0^{\circ}) - cot (69 0^{\circ})

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arctan (\frac{50}{40})