sin(90-x)= 4/5

解答

sin (9 0^{\circ} - x^{\circ}) = \frac{4}{5}

x \in R 无解

求解步骤

sin (9 0^{\circ} - x^{\circ}) = \frac{4}{5}

使用反三角函数性质

sin (9 0^{\circ} - x^{\circ}) = \frac{4}{5}

sin (9 0^{\circ} - x^{\circ}) = \frac{4}{5}

的通解

sin (x) = a \Rightarrow x = arcsin (a) + 36 0^{\circ} n, x = 18 0^{\circ} - arcsin (a) + 36 0^{\circ} n

9 0^{\circ} - x^{\circ} = arcsin (\frac{4}{5}) + 36 0^{\circ} n, 9 0^{\circ} - x^{\circ} = 18 0^{\circ} - arcsin (\frac{4}{5}) + 36 0^{\circ} n

9 0^{\circ} - x^{\circ} = arcsin (\frac{4}{5}) + 36 0^{\circ} n, 9 0^{\circ} - x^{\circ} = 18 0^{\circ} - arcsin (\frac{4}{5}) + 36 0^{\circ} n

x \in R 无解

sin (x) = sin (8 0^{\circ})

tan (A) = 2.0503

2 sin (4 x) - 1 = 0

cot (θ) = 0.75

6 sin (x) - 2 cos (x) = 2