Graph of the function intersects the axis X at f = 0
so we need to solve the equation:
$$\sin{\left(\frac{6 x}{5} \right)} = 0$$
Solve this equationThe points of intersection with the axis X:
Analytical solution$$x_{1} = 0$$
$$x_{2} = \frac{5 \pi}{6}$$
Numerical solution$$x_{1} = 62.8318530717959$$
$$x_{2} = 2.61799387799149$$
$$x_{3} = 73.3038285837618$$
$$x_{4} = -41.8879020478639$$
$$x_{5} = -70.6858347057703$$
$$x_{6} = 81.1578102177363$$
$$x_{7} = -18.3259571459405$$
$$x_{8} = 44.5058959258554$$
$$x_{9} = 7.85398163397448$$
$$x_{10} = -68.0678408277789$$
$$x_{11} = -99.4837673636768$$
$$x_{12} = 96.8657734856853$$
$$x_{13} = 91.6297857297023$$
$$x_{14} = -49.7418836818384$$
$$x_{15} = -89.0117918517108$$
$$x_{16} = -54.9778714378214$$
$$x_{17} = -94.2477796076938$$
$$x_{18} = 52.3598775598299$$
$$x_{19} = -15.707963267949$$
$$x_{20} = -73.3038285837618$$
$$x_{21} = 20.943951023932$$
$$x_{22} = -52.3598775598299$$
$$x_{23} = 23.5619449019235$$
$$x_{24} = -340.339204138894$$
$$x_{25} = 57.5958653158129$$
$$x_{26} = 5.23598775598299$$
$$x_{27} = 41.8879020478639$$
$$x_{28} = 34.0339204138894$$
$$x_{29} = -96.8657734856853$$
$$x_{30} = 60.2138591938044$$
$$x_{31} = -44.5058959258554$$
$$x_{32} = 31.4159265358979$$
$$x_{33} = 10.471975511966$$
$$x_{34} = -86.3937979737193$$
$$x_{35} = 15.707963267949$$
$$x_{36} = -83.7758040957278$$
$$x_{37} = 94.2477796076938$$
$$x_{38} = -1073.37748997651$$
$$x_{39} = 75.9218224617533$$
$$x_{40} = 86.3937979737193$$
$$x_{41} = 36.6519142918809$$
$$x_{42} = -60.2138591938044$$
$$x_{43} = 39.2699081698724$$
$$x_{44} = -39.2699081698724$$
$$x_{45} = -91.6297857297023$$
$$x_{46} = 83.7758040957278$$
$$x_{47} = 28.7979326579064$$
$$x_{48} = 115.191730631626$$
$$x_{49} = -36.6519142918809$$
$$x_{50} = -10.471975511966$$
$$x_{51} = 0$$
$$x_{52} = 18.3259571459405$$
$$x_{53} = -13.0899693899575$$
$$x_{54} = -65.4498469497874$$
$$x_{55} = -5.23598775598299$$
$$x_{56} = 54.9778714378214$$
$$x_{57} = -62.8318530717959$$
$$x_{58} = -34.0339204138894$$
$$x_{59} = -81.1578102177363$$
$$x_{60} = -26.1799387799149$$
$$x_{61} = -3293.4362985133$$
$$x_{62} = 49.7418836818384$$
$$x_{63} = -23.5619449019235$$
$$x_{64} = 47.1238898038469$$
$$x_{65} = 99.4837673636768$$
$$x_{66} = 78.5398163397448$$
$$x_{67} = 70.6858347057703$$
$$x_{68} = -28.7979326579064$$
$$x_{69} = 65.4498469497874$$
$$x_{70} = -20.943951023932$$
$$x_{71} = -78.5398163397448$$
$$x_{72} = -31.4159265358979$$
$$x_{73} = -57.5958653158129$$
$$x_{74} = -2.61799387799149$$
$$x_{75} = 68.0678408277789$$
$$x_{76} = 26.1799387799149$$
$$x_{77} = 13.0899693899575$$
$$x_{78} = -7.85398163397448$$
$$x_{79} = 89.0117918517108$$
$$x_{80} = -75.9218224617533$$
$$x_{81} = -47.1238898038469$$