Graph of the function intersects the axis X at f = 0
so we need to solve the equation:
$$\sin{\left(\sin{\left(x x \right)} \right)} = 0$$
Solve this equationThe points of intersection with the axis X:
Analytical solution$$x_{1} = 0$$
$$x_{2} = - \sqrt{\pi}$$
$$x_{3} = \sqrt{\pi}$$
Numerical solution$$x_{1} = -57.8971446738119$$
$$x_{2} = -89.7498945058111$$
$$x_{3} = 0$$
$$x_{4} = 6.13996024767893$$
$$x_{5} = 18.2485292908913$$
$$x_{6} = -15.7539144225679$$
$$x_{7} = -97.9030090758321$$
$$x_{8} = -17.9884419369702$$
$$x_{9} = 28.2482660354898$$
$$x_{10} = 62.1118006389146$$
$$x_{11} = 48.2810702963763$$
$$x_{12} = -33.862683274665$$
$$x_{13} = -27.7432910832421$$
$$x_{14} = -81.0498009785111$$
$$x_{15} = 90.9322377611391$$
$$x_{16} = -17.4566459378143$$
$$x_{17} = 56.3852087469123$$
$$x_{18} = -43.8480866628973$$
$$x_{19} = 50.226476094114$$
$$x_{20} = -59.8449298194288$$
$$x_{21} = -7.72594721818665$$
$$x_{22} = 56.273665198017$$
$$x_{23} = 68.1646208429219$$
$$x_{24} = -93.8564105464607$$
$$x_{25} = -9.86860538583257$$
$$x_{26} = -27.4587369859131$$
$$x_{27} = 20.3639443692486$$
$$x_{28} = 58.3026864834216$$
$$x_{29} = 16.244807875181$$
$$x_{30} = 42.2424505354389$$
$$x_{31} = -77.1984537659909$$
$$x_{32} = -11.6227571644753$$
$$x_{33} = 46.3217851815086$$
$$x_{34} = 98.1113647372165$$
$$x_{35} = 3.96332729760601$$
$$x_{36} = 52.2498231190263$$
$$x_{37} = 85.4278627514998$$
$$x_{38} = -85.4646296405494$$
$$x_{39} = -3.96332729760601$$
$$x_{40} = -41.8689467350578$$
$$x_{41} = -71.9100932262558$$
$$x_{42} = -29.9749144940679$$
$$x_{43} = 64.2499240996983$$
$$x_{44} = 82.1853040708499$$
$$x_{45} = 70.185591689668$$
$$x_{46} = -31.6073798952326$$
$$x_{47} = -91.6720259858628$$
$$x_{48} = 30.027272463217$$
$$x_{49} = 78.4098005550022$$
$$x_{50} = 22.137941502317$$
$$x_{51} = 32.1494009746845$$
$$x_{52} = 94.1238082693386$$
$$x_{53} = 8.1224039375905$$
$$x_{54} = -19.8166364880301$$
$$x_{55} = 223.20958288855$$
$$x_{56} = 11.2099824327959$$
$$x_{57} = -16.8149736491938$$
$$x_{58} = 65.4849140806497$$
$$x_{59} = 74.6116759104171$$
$$x_{60} = 91.1392943580946$$
$$x_{61} = -22.0668724858422$$
$$x_{62} = -47.4276326625132$$
$$x_{63} = -5.87856438167413$$
$$x_{64} = -1.77245385090552$$