cos(x)=-0.45

解答

cos (x) = - 0.45

x = 2.03756 \dots + 2 πn, x = - 2.03756 \dots + 2 πn

度数

x = 116.74368 \dots^{\circ} + 36 0^{\circ} n, x = - 116.74368 \dots^{\circ} + 36 0^{\circ} n

求解步骤

cos (x) = - 0.45

使用反三角函数性质

cos (x) = - 0.45

cos (x) = - 0.45

的通解

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

x = arccos (- 0.45) + 2 πn, x = - arccos (- 0.45) + 2 πn

x = arccos (- 0.45) + 2 πn, x = - arccos (- 0.45) + 2 πn

以小数形式表示解

x = 2.03756 \dots + 2 πn, x = - 2.03756 \dots + 2 πn

sin (4 x) cos (x) - sin (x) cos (4 x) = - \frac{1}{2}

4 tan (θ) - 1 = 0

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27 sin (t) cos (t) = - 3 sin (t)

sin (5 x) - sin (x) + 3 cos (3 x) = 0