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受欢迎的三角函数 >

4.72^2=3.3^2+3.3^2-2(3.3)(3.3)cos(x)

解答

4.7 2^{2} = 3. 3^{2} + 3. 3^{2} - 2 (3.3) (3.3) cos (x)

解答

x = 1.59368 \dots + 2 πn, x = - 1.59368 \dots + 2 πn

+1

度数

x = 91.31123 \dots^{\circ} + 36 0^{\circ} n, x = - 91.31123 \dots^{\circ} + 36 0^{\circ} n

求解步骤

4.7 2^{2} = 3. 3^{2} + 3. 3^{2} - 2 (3.3) (3.3) cos (x)

交换两边

3. 3^{2} + 3. 3^{2} - 2 \cdot 3.3 \cdot 3.3 cos (x) = 4.7 2^{2}

化简

3. 3^{2} + 3. 3^{2} - 2 \cdot 3.3 \cdot 3.3 cos (x) : 21.78 - 21.78 cos (x)

3. 3^{2} + 3. 3^{2} - 2 \cdot 3.3 \cdot 3.3 cos (x)

同类项相加:

3. 3^{2} + 3. 3^{2} = 2 \cdot 3. 3^{2}

= 2 \cdot 3. 3^{2} - 2 \cdot 3.3 \cdot 3.3 cos (x)

数字相乘:

2 \cdot 3.3 \cdot 3.3 = 21.78

= 2 \cdot 3. 3^{2} - 21.78 cos (x)

2 \cdot 3. 3^{2} = 21.78

2 \cdot 3. 3^{2}

3. 3^{2} = 10.89

= 2 \cdot 10.89

数字相乘:

2 \cdot 10.89 = 21.78

= 21.78

= 21.78 - 21.78 cos (x)

化简

4.7 2^{2} : 22.2784

4.7 2^{2}

4.7 2^{2} = 22.2784

= 22.2784

21.78 - 21.78 cos (x) = 22.2784

将

21.78

到右边

21.78 - 21.78 cos (x) = 22.2784

两边减去

21.78

21.78 - 21.78 cos (x) - 21.78 = 22.2784 - 21.78

化简

- 21.78 cos (x) = 0.4984

- 21.78 cos (x) = 0.4984

两边除以

- 21.78

- 21.78 cos (x) = 0.4984

两边除以

- 21.78

\frac{- 21.78 cos ( x )}{- 21.78} = \frac{0.4984}{- 21.78}

化简

cos (x) = - \frac{0.4984}{21.78}

cos (x) = - \frac{0.4984}{21.78}

使用反三角函数性质

cos (x) = - \frac{0.4984}{21.78}

cos (x) = - \frac{0.4984}{21.78}

的通解

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

x = arccos (- \frac{0.4984}{21.78}) + 2 πn, x = - arccos (- \frac{0.4984}{21.78}) + 2 πn

x = arccos (- \frac{0.4984}{21.78}) + 2 πn, x = - arccos (- \frac{0.4984}{21.78}) + 2 πn

以小数形式表示解

x = 1.59368 \dots + 2 πn, x = - 1.59368 \dots + 2 πn

作图

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