cos(a)=(-11)/(14)

解答

cos (a) = \frac{- 11}{14}

a = 2.47464 \dots + 2 πn, a = - 2.47464 \dots + 2 πn

度数

a = 141.78678 \dots^{\circ} + 36 0^{\circ} n, a = - 141.78678 \dots^{\circ} + 36 0^{\circ} n

求解步骤

cos (a) = \frac{- 11}{14}

使用分式法则:

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

cos (a) = - \frac{11}{14}

使用反三角函数性质

cos (a) = - \frac{11}{14}

cos (a) = - \frac{11}{14}

的通解

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

a = arccos (- \frac{11}{14}) + 2 πn, a = - arccos (- \frac{11}{14}) + 2 πn

a = arccos (- \frac{11}{14}) + 2 πn, a = - arccos (- \frac{11}{14}) + 2 πn

以小数形式表示解

a = 2.47464 \dots + 2 πn, a = - 2.47464 \dots + 2 πn

so l v e f or x, sin (\frac{x}{x}) = 0.7

5 cos^{2} (x) + sin^{2} (x) = 4

cos (u) - 1.5 sin^{2} (u) + 0.1667 = 0

3 sin (2 x - 1) = 1

so l v e f or m, sec (m + 1 2^{\circ}) = csc (4 2^{\circ} - n)