zs

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

受欢迎的三角函数 >

cos(α)=sqrt((1+1/5)/2)

解答

cos (α) = \frac{1 + \frac{1}{5}}{2}

解答

α = 0.68471 \dots + 2 πn, α = 2 π - 0.68471 \dots + 2 πn

+1

度数

α = 39.23152 \dots^{\circ} + 36 0^{\circ} n, α = 320.76847 \dots^{\circ} + 36 0^{\circ} n

求解步骤

cos (α) = \frac{1 + \frac{1}{5}}{2}

\frac{1 + \frac{1}{5}}{2} = \frac{3}{5}

\frac{1 + \frac{1}{5}}{2}

化简

1 + \frac{1}{5} : \frac{6}{5}

1 + \frac{1}{5}

将项转换为分式:

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

= \frac{1 \cdot 5}{5} + \frac{1}{5}

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{1 \cdot 5 + 1}{5}

1 \cdot 5 + 1 = 6

1 \cdot 5 + 1

数字相乘:

1 \cdot 5 = 5

= 5 + 1

数字相加:

5 + 1 = 6

= 6

= \frac{6}{5}

= \frac{\frac{6}{5}}{2}

使用分式法则:

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

= \frac{6}{5 \cdot 2}

数字相乘:

5 \cdot 2 = 10

= \frac{6}{10}

约分:

2

= \frac{3}{5}

cos (α) = \frac{3}{5}

使用反三角函数性质

cos (α) = \frac{3}{5}

cos (α) = \frac{3}{5}

的通解

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

α = arccos (\frac{3}{5}) + 2 πn, α = 2 π - arccos (\frac{3}{5}) + 2 πn

α = arccos (\frac{3}{5}) + 2 πn, α = 2 π - arccos (\frac{3}{5}) + 2 πn

以小数形式表示解

α = 0.68471 \dots + 2 πn, α = 2 π - 0.68471 \dots + 2 πn

作图

流行的例子

(tan(x))(sin^2(x)-a)(sec(x)-a)=0,0<a<1

(tan (x)) (sin^{2} (x) - a) (sec (x) - a) = 0, 0 < a < 1

sin(pi/2 (x+1))= 2/5

sin (\frac{π}{2} (x + 1)) = \frac{2}{5}

sin(*+pi/2)=cos(x)

sin (\cdot + \frac{π}{2}) = cos (x)

sin(θ)=(0.000069)2(500*10^{-9})

sin (θ) = (0.000069) 2 (500 \cdot 1 0^{- 9})

(2sin^2(x)-1)(tan(x)-1)=0

(2 sin^{2} (x) - 1) (tan (x) - 1) = 0