cos(θ)= 11/61

解答

cos (θ) = \frac{11}{61}

θ = 1.38947 \dots + 2 πn, θ = 2 π - 1.38947 \dots + 2 πn

度数

θ = 79.61114 \dots^{\circ} + 36 0^{\circ} n, θ = 280.38885 \dots^{\circ} + 36 0^{\circ} n

求解步骤

cos (θ) = \frac{11}{61}

使用反三角函数性质

cos (θ) = \frac{11}{61}

cos (θ) = \frac{11}{61}

的通解

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

θ = arccos (\frac{11}{61}) + 2 πn, θ = 2 π - arccos (\frac{11}{61}) + 2 πn

θ = arccos (\frac{11}{61}) + 2 πn, θ = 2 π - arccos (\frac{11}{61}) + 2 πn

以小数形式表示解

θ = 1.38947 \dots + 2 πn, θ = 2 π - 1.38947 \dots + 2 πn