cos(x)= 67/77

解答

cos (x) = \frac{67}{77}

x = 0.51533 \dots + 2 πn, x = 2 π - 0.51533 \dots + 2 πn

度数

x = 29.52626 \dots^{\circ} + 36 0^{\circ} n, x = 330.47373 \dots^{\circ} + 36 0^{\circ} n

求解步骤

cos (x) = \frac{67}{77}

使用反三角函数性质

cos (x) = \frac{67}{77}

cos (x) = \frac{67}{77}

的通解

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

x = arccos (\frac{67}{77}) + 2 πn, x = 2 π - arccos (\frac{67}{77}) + 2 πn

x = arccos (\frac{67}{77}) + 2 πn, x = 2 π - arccos (\frac{67}{77}) + 2 πn

以小数形式表示解

x = 0.51533 \dots + 2 πn, x = 2 π - 0.51533 \dots + 2 πn

(sin (x) + cos (x))^{2} = \frac{1 + 2 sin ( x )}{sec ( x )}

cot (\frac{π}{3}) = tan (x)

3 cot (x) + 1 = 2 + 4 cot (x), 0^{\circ} \leq x \leq 36 0^{\circ}

sin (x) = \frac{48.35}{50.14}

1.47 = (\frac{sin ( \frac{x + 60}{2} )}{sin ( 3 0 ^{\circ} )})