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受欢迎的三角函数 >

sqrt(1-cos^2(x))=0.75sqrt(1-cos^2(y))

解答

1 - cos^{2} (x) = 0.75 1 - cos^{2} (y)

解答

x = arccos (0.5625 cos^{2} (y) + 0.4375) + 2 πn, x = - arccos (0.5625 cos^{2} (y) + 0.4375) + 2 πn, x = arccos (- 0.5625 cos^{2} (y) + 0.4375) + 2 πn, x = - arccos (- 0.5625 cos^{2} (y) + 0.4375) + 2 πn

求解步骤

1 - cos^{2} (x) = 0.75 1 - cos^{2} (y)

用替代法求解

1 - cos^{2} (x) = 0.75 1 - cos^{2} (y)

令

: cos (x) = u

1 - u^{2} = 0.75 1 - cos^{2} (y)

1 - u^{2} = 0.75 1 - cos^{2} (y) : u = 0.5625 cos^{2} (y) + 0.4375, u = - 0.5625 cos^{2} (y) + 0.4375

1 - u^{2} = 0.75 1 - cos^{2} (y)

两边进行平方:

1 - u^{2} = 0.5625 - 0.5625 cos^{2} (y)

1 - u^{2} = 0.75 1 - cos^{2} (y)

(1 - u^{2})^{2} = (0.75 1 - cos^{2} (y))^{2}

展开

(1 - u^{2})^{2} : 1 - u^{2}

(1 - u^{2})^{2}

使用根式运算法则:

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

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

使用指数法则:

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

= (1 - u^{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

= 1 - u^{2}

展开

(0.75 1 - cos^{2} (y))^{2} : 0.5625 - 0.5625 cos^{2} (y)

(0.75 1 - cos^{2} (y))^{2}

使用指数法则:

(a \cdot b)^{n} = a^{n} b^{n}

= 0.7 5^{2} (- cos^{2} (y) + 1)^{2}

(1 - cos^{2} (y))^{2} : 1 - cos^{2} (y)

使用根式运算法则:

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

= ((1 - cos^{2} (y))^{\frac{1}{2}})^{2}

使用指数法则:

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

= (1 - cos^{2} (y))^{\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

= 1 - cos^{2} (y)

= 0.7 5^{2} (1 - cos^{2} (y))

0.7 5^{2} = 0.5625

= 0.5625 (- cos^{2} (y) + 1)

使用分配律:

a (b - c) = ab - a c

a = 0.5625, b = 1, c = cos^{2} (y)

= 0.5625 \cdot 1 - 0.5625 cos^{2} (y)

= 1 \cdot 0.5625 - 0.5625 cos^{2} (y)

数字相乘:

1 \cdot 0.5625 = 0.5625

= 0.5625 - 0.5625 cos^{2} (y)

1 - u^{2} = 0.5625 - 0.5625 cos^{2} (y)

1 - u^{2} = 0.5625 - 0.5625 cos^{2} (y)

解

1 - u^{2} = 0.5625 - 0.5625 cos^{2} (y) : u = 0.5625 cos^{2} (y) + 0.4375, u = - 0.5625 cos^{2} (y) + 0.4375

1 - u^{2} = 0.5625 - 0.5625 cos^{2} (y)

将

1

到右边

1 - u^{2} = 0.5625 - 0.5625 cos^{2} (y)

两边减去

1

1 - u^{2} - 1 = 0.5625 - 0.5625 cos^{2} (y) - 1

化简

- u^{2} = - 0.5625 cos^{2} (y) - 0.4375

- u^{2} = - 0.5625 cos^{2} (y) - 0.4375

两边除以

- 1

- u^{2} = - 0.5625 cos^{2} (y) - 0.4375

两边除以

- 1

\frac{- u ^{2}}{- 1} = - \frac{0.5625 cos ^{2} ( y )}{- 1} - \frac{0.4375}{- 1}

化简

\frac{- u ^{2}}{- 1} = - \frac{0.5625 cos ^{2} ( y )}{- 1} - \frac{0.4375}{- 1}

化简

\frac{- u ^{2}}{- 1} : u^{2}

\frac{- u ^{2}}{- 1}

使用分式法则:

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

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

使用法则

\frac{a}{1} = a

= u^{2}

化简

- \frac{0.5625 cos ^{2} ( y )}{- 1} - \frac{0.4375}{- 1} : 0.5625 cos^{2} (y) + 0.4375

- \frac{0.5625 cos ^{2} ( y )}{- 1} - \frac{0.4375}{- 1}

使用法则

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

= \frac{- 0.5625 cos ^{2} ( y ) - 0.4375}{- 1}

使用分式法则:

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

= - \frac{- 0.5625 cos ^{2} ( y ) - 0.4375}{1}

使用法则

\frac{a}{1} = a

= - (- 0.5625 cos^{2} (y) - 0.4375)

打开括号

= - (- 0.5625 cos^{2} (y)) - (- 0.4375)

使用加减运算法则

- (- a) = a

= 0.5625 cos^{2} (y) + 0.4375

u^{2} = 0.5625 cos^{2} (y) + 0.4375

u^{2} = 0.5625 cos^{2} (y) + 0.4375

u^{2} = 0.5625 cos^{2} (y) + 0.4375

对于

x^{2} = f (a)

解为

x = f (a), - f (a)

u = 0.5625 cos^{2} (y) + 0.4375, u = - 0.5625 cos^{2} (y) + 0.4375

u = 0.5625 cos^{2} (y) + 0.4375, u = - 0.5625 cos^{2} (y) + 0.4375

验证解:

u = 0.5625 cos^{2} (y) + 0.4375

真

, u = - 0.5625 cos^{2} (y) + 0.4375

真

将它们代入

1 - u^{2} = 0.75 1 - cos^{2} (y)

检验解是否符合

去除与方程不符的解。

代入

u = 0.5625 cos^{2} (y) + 0.4375 :

真

1 - (0.5625 cos^{2} (y) + 0.4375)^{2} = 0.75 1 - cos^{2} (y)

化简

1 - (0.5625 cos^{2} (y) + 0.4375)^{2} : - 0.5625 cos^{2} (y) + 0.5625

1 - (0.5625 cos^{2} (y) + 0.4375)^{2}

(0.5625 cos^{2} (y) + 0.4375)^{2} = 0.5625 cos^{2} (y) + 0.4375

(0.5625 cos^{2} (y) + 0.4375)^{2}

使用根式运算法则:

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

= ((0.5625 cos^{2} (y) + 0.4375)^{\frac{1}{2}})^{2}

使用指数法则:

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

= (0.5625 cos^{2} (y) + 0.4375)^{\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

= 0.5625 cos^{2} (y) + 0.4375

= 1 - (0.5625 cos^{2} (y) + 0.4375)

乘开

1 - (0.5625 cos^{2} (y) + 0.4375) : - 0.5625 cos^{2} (y) + 0.5625

1 - (0.5625 cos^{2} (y) + 0.4375)

- (0.5625 cos^{2} (y) + 0.4375) : - 0.5625 cos^{2} (y) - 0.4375

- (0.5625 cos^{2} (y) + 0.4375)

打开括号

= - (0.5625 cos^{2} (y)) - (0.4375)

使用加减运算法则

+ (- a) = - a

= - 0.5625 cos^{2} (y) - 0.4375

= 1 - 0.5625 cos^{2} (y) - 0.4375

数字相减:

1 - 0.4375 = 0.5625

= - 0.5625 cos^{2} (y) + 0.5625

= - 0.5625 cos^{2} (y) + 0.5625

- 0.5625 cos^{2} (y) + 0.5625 = 0.75 1 - cos^{2} (y)

真

代入

u = - 0.5625 cos^{2} (y) + 0.4375 :

真

1 - (- 0.5625 cos^{2} (y) + 0.4375)^{2} = 0.75 1 - cos^{2} (y)

化简

1 - (- 0.5625 cos^{2} (y) + 0.4375)^{2} : - 0.5625 cos^{2} (y) + 0.5625

1 - (- 0.5625 cos^{2} (y) + 0.4375)^{2}

(- 0.5625 cos^{2} (y) + 0.4375)^{2} = 0.5625 cos^{2} (y) + 0.4375

(- 0.5625 cos^{2} (y) + 0.4375)^{2}

使用指数法则:

(- a)^{n} = a^{n},

若

n

是偶数

(- 0.5625 cos^{2} (y) + 0.4375)^{2} = (0.5625 cos^{2} (y) + 0.4375)^{2}

= (0.5625 cos^{2} (y) + 0.4375)^{2}

使用根式运算法则:

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

= ((0.5625 cos^{2} (y) + 0.4375)^{\frac{1}{2}})^{2}

使用指数法则:

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

= (0.5625 cos^{2} (y) + 0.4375)^{\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

= 0.5625 cos^{2} (y) + 0.4375

= 1 - (0.5625 cos^{2} (y) + 0.4375)

乘开

1 - (0.5625 cos^{2} (y) + 0.4375) : - 0.5625 cos^{2} (y) + 0.5625

1 - (0.5625 cos^{2} (y) + 0.4375)

- (0.5625 cos^{2} (y) + 0.4375) : - 0.5625 cos^{2} (y) - 0.4375

- (0.5625 cos^{2} (y) + 0.4375)

打开括号

= - (0.5625 cos^{2} (y)) - (0.4375)

使用加减运算法则

+ (- a) = - a

= - 0.5625 cos^{2} (y) - 0.4375

= 1 - 0.5625 cos^{2} (y) - 0.4375

数字相减:

1 - 0.4375 = 0.5625

= - 0.5625 cos^{2} (y) + 0.5625

= - 0.5625 cos^{2} (y) + 0.5625

- 0.5625 cos^{2} (y) + 0.5625 = 0.75 1 - cos^{2} (y)

真

解为

u = 0.5625 cos^{2} (y) + 0.4375, u = - 0.5625 cos^{2} (y) + 0.4375

u = cos (x)

代回

cos (x) = 0.5625 cos^{2} (y) + 0.4375, cos (x) = - 0.5625 cos^{2} (y) + 0.4375

cos (x) = 0.5625 cos^{2} (y) + 0.4375, cos (x) = - 0.5625 cos^{2} (y) + 0.4375

cos (x) = 0.5625 cos^{2} (y) + 0.4375 : x = arccos (0.5625 cos^{2} (y) + 0.4375) + 2 πn, x = - arccos (0.5625 cos^{2} (y) + 0.4375) + 2 πn

cos (x) = 0.5625 cos^{2} (y) + 0.4375

使用反三角函数性质

cos (x) = 0.5625 cos^{2} (y) + 0.4375

cos (x) = 0.5625 cos^{2} (y) + 0.4375

的通解

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

x = arccos (0.5625 cos^{2} (y) + 0.4375) + 2 πn, x = - arccos (0.5625 cos^{2} (y) + 0.4375) + 2 πn

x = arccos (0.5625 cos^{2} (y) + 0.4375) + 2 πn, x = - arccos (0.5625 cos^{2} (y) + 0.4375) + 2 πn

cos (x) = - 0.5625 cos^{2} (y) + 0.4375 : x = arccos (- 0.5625 cos^{2} (y) + 0.4375) + 2 πn, x = - arccos (- 0.5625 cos^{2} (y) + 0.4375) + 2 πn

cos (x) = - 0.5625 cos^{2} (y) + 0.4375

使用反三角函数性质

cos (x) = - 0.5625 cos^{2} (y) + 0.4375

cos (x) = - 0.5625 cos^{2} (y) + 0.4375

的通解

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

x = arccos (- 0.5625 cos^{2} (y) + 0.4375) + 2 πn, x = - arccos (- 0.5625 cos^{2} (y) + 0.4375) + 2 πn

x = arccos (- 0.5625 cos^{2} (y) + 0.4375) + 2 πn, x = - arccos (- 0.5625 cos^{2} (y) + 0.4375) + 2 πn

合并所有解

x = arccos (0.5625 cos^{2} (y) + 0.4375) + 2 πn, x = - arccos (0.5625 cos^{2} (y) + 0.4375) + 2 πn, x = arccos (- 0.5625 cos^{2} (y) + 0.4375) + 2 πn, x = - arccos (- 0.5625 cos^{2} (y) + 0.4375) + 2 πn

作图

流行的例子

sec^2(x)-6tan(x)+4=0

sec^{2} (x) - 6 tan (x) + 4 = 0

1-cos(x)=2-2sin^2(x)

1 - cos (x) = 2 - 2 sin^{2} (x)

-5tan(x)-12=tan(x)-8

- 5 tan (x) - 12 = tan (x) - 8

5 = sec^{2} (x) + 3

sin (θ) = \frac{24}{25}