arcsin(cos(120))

解答

arcsin (cos (12 0^{\circ}))

- \frac{π}{6}

十进制

- 30

求解步骤

arcsin (cos (12 0^{\circ}))

使用三角恒等式改写:

cos (12 0^{\circ}) = sin (- 3 0^{\circ})

cos (12 0^{\circ})

sin (9 0^{\circ} - x) = cos (x)

= sin (9 0^{\circ} - 12 0^{\circ})

= sin (- 3 0^{\circ})

= arcsin (sin (- 3 0^{\circ}))

Use the inverse trig property:

- 3 0^{\circ}

arcsin (sin (- 3 0^{\circ}))

对于

- 9 0^{\circ} \leq x \leq 9 0^{\circ}, a rcs in (s in (x)) = x

- 9 0^{\circ} \leq - 3 0^{\circ} \leq 9 0^{\circ}

= - 3 0^{\circ}

= - 3 0^{\circ}