#!/usr/bin/python3
# ===================================================================
# demonstrate numpy.arcsin
# -------------------------------------------------------------------
# input : to   arcsin is y-coordinate on the unit circle
# output: from arcsin is the inverse sine in radians and in the
#         closed interval [-pi/2, pi/2] radians
#                         [-90, 90] degrees
# -------------------------------------------------------------------
# output of program:
#    deg      rad        sin        arcsin_rad    arsin_deg
#      0      0.000      0.000      0.000           0.00
#     45      0.785      0.707      0.785          45.00
#     90      1.571      1.000      1.571          90.00
#    135      2.356      0.707      0.785          45.00
#    180      3.142      0.000      0.000           0.00
#    225      3.927     -0.707     -0.785         -45.00
#    270      4.712     -1.000     -1.571         -90.00
#    315      5.498     -0.707     -0.785         -45.00
#    360      6.283     -0.000     -0.000          -0.00
# ===================================================================

import numpy as np

print('deg      rad        sin        arcsin_rad    arsin_deg')

for deg in range(0,361,45):
    fdeg = float(deg)
    rad  = np.deg2rad(fdeg)
    rsin = np.sin(rad)

    r = np.arcsin(np.sin(rad))     # arcsin returns radians
    d = np.rad2deg(r)              # convert arcsin radians
                                   # to degrees

    print(f'{deg:3}     {rad:6.3f}     {rsin:6.3f}     {r:6.3f}' +
          f'         {d:6.2f}')