Graph of the function intersects the axis X at f = 0
so we need to solve the equation:
$$2 \sin{\left(x \right)} + 1 = 0$$
Solve this equationThe points of intersection with the axis X:
Analytical solution$$x_{1} = - \frac{\pi}{6}$$
$$x_{2} = \frac{7 \pi}{6}$$
Numerical solution$$x_{1} = 9.94837673636768$$
$$x_{2} = -75.9218224617533$$
$$x_{3} = 37.1755130674792$$
$$x_{4} = 74.8746249105567$$
$$x_{5} = 24.60914245312$$
$$x_{6} = 60.2138591938044$$
$$x_{7} = -15.1843644923507$$
$$x_{8} = -101.054563690472$$
$$x_{9} = -31.9395253114962$$
$$x_{10} = -25.6563400043166$$
$$x_{11} = 93.7241808320955$$
$$x_{12} = -195.302343298165$$
$$x_{13} = -52.8834763354282$$
$$x_{14} = 85.3466004225227$$
$$x_{15} = -0.523598775598299$$
$$x_{16} = -38.2227106186758$$
$$x_{17} = -57.0722665402146$$
$$x_{18} = -84.2994028713261$$
$$x_{19} = -90.5825881785057$$
$$x_{20} = 62.3082542961976$$
$$x_{21} = 66.497044500984$$
$$x_{22} = 16.2315620435473$$
$$x_{23} = 22.5147473507269$$
$$x_{24} = 28.7979326579064$$
$$x_{25} = 12.0427718387609$$
$$x_{26} = -46.6002910282486$$
$$x_{27} = -78.0162175641465$$
$$x_{28} = -82.2050077689329$$
$$x_{29} = 100.007366139275$$
$$x_{30} = 5.75958653158129$$
$$x_{31} = -8.90117918517108$$
$$x_{32} = -13.0899693899575$$
$$x_{33} = -88.4881930761125$$
$$x_{34} = 437.20497762458$$
$$x_{35} = -94.7713783832921$$
$$x_{36} = -65.4498469497874$$
$$x_{37} = 79.0634151153431$$
$$x_{38} = -19.3731546971371$$
$$x_{39} = 56.025068989018$$
$$x_{40} = -34.0339204138894$$
$$x_{41} = -63.3554518473942$$
$$x_{42} = 91.6297857297023$$
$$x_{43} = -44.5058959258554$$
$$x_{44} = -6.80678408277789$$
$$x_{45} = -2.61799387799149$$
$$x_{46} = 72.7802298081635$$
$$x_{47} = 192.160750644576$$
$$x_{48} = 35.081117965086$$
$$x_{49} = -40.317105721069$$
$$x_{50} = 97.9129710368819$$
$$x_{51} = -96.8657734856853$$
$$x_{52} = -151.320046147908$$
$$x_{53} = 87.4409955249159$$
$$x_{54} = 81.1578102177363$$
$$x_{55} = 66400.1787274983$$
$$x_{56} = 53.9306738866248$$
$$x_{57} = 68.5914396033772$$
$$x_{58} = 3.66519142918809$$
$$x_{59} = -71.733032256967$$
$$x_{60} = -50.789081233035$$
$$x_{61} = -59.1666616426078$$
$$x_{62} = 30.8923277602996$$
$$x_{63} = 47.6474885794452$$
$$x_{64} = -27.7507351067098$$
$$x_{65} = 18.3259571459405$$
$$x_{66} = 43.4586983746588$$
$$x_{67} = 41.3643032722656$$
$$x_{68} = -21.4675497995303$$
$$x_{69} = 49.7418836818384$$
$$x_{70} = -69.6386371545737$$