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受欢迎的三角函数 >

5^2=8^2-(11.85)^2-2(8)(11.85)(cos(A))

解答

5^{2} = 8^{2} - (11.85)^{2} - 2 (8) (11.85) (cos (A))

解答

A = 2.13521 \dots + 2 πn, A = - 2.13521 \dots + 2 πn

+1

度数

A = 122.33908 \dots^{\circ} + 36 0^{\circ} n, A = - 122.33908 \dots^{\circ} + 36 0^{\circ} n

求解步骤

5^{2} = 8^{2} - (11.85)^{2} - 2 (8) (11.85) (cos (A))

交换两边

8^{2} - 11.8 5^{2} - 2 \cdot 8 \cdot 11.85 cos (A) = 5^{2}

数字相乘:

2 \cdot 8 \cdot 11.85 = 189.6

8^{2} - 11.8 5^{2} - 189.6 cos (A) = 5^{2}

8^{2} = 64

64 - 11.8 5^{2} - 189.6 cos (A) = 5^{2}

11.8 5^{2} = 140.4225

64 - 140.4225 - 189.6 cos (A) = 5^{2}

数字相减:

64 - 140.4225 = - 76.4225

- 189.6 cos (A) - 76.4225 = 5^{2}

5^{2} = 25

- 189.6 cos (A) - 76.4225 = 25

将

76.4225

到右边

- 189.6 cos (A) - 76.4225 = 25

两边加上

76.4225

- 189.6 cos (A) - 76.4225 + 76.4225 = 25 + 76.4225

化简

- 189.6 cos (A) = 101.4225

- 189.6 cos (A) = 101.4225

两边除以

- 189.6

- 189.6 cos (A) = 101.4225

两边除以

- 189.6

\frac{- 189.6 cos ( A )}{- 189.6} = \frac{101.4225}{- 189.6}

化简

cos (A) = - \frac{101.4225}{189.6}

cos (A) = - \frac{101.4225}{189.6}

使用反三角函数性质

cos (A) = - \frac{101.4225}{189.6}

cos (A) = - \frac{101.4225}{189.6}

的通解

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

A = arccos (- \frac{101.4225}{189.6}) + 2 πn, A = - arccos (- \frac{101.4225}{189.6}) + 2 πn

A = arccos (- \frac{101.4225}{189.6}) + 2 πn, A = - arccos (- \frac{101.4225}{189.6}) + 2 πn

以小数形式表示解

A = 2.13521 \dots + 2 πn, A = - 2.13521 \dots + 2 πn

作图

流行的例子

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(cosh(x))=sinh(x)

(cosh (x)) = sinh (x)