Graph of the function intersects the axis T at f = 0
so we need to solve the equation:
$$3 \sin{\left(t \right)} = 0$$
Solve this equationThe points of intersection with the axis T:
Analytical solution$$t_{1} = 0$$
$$t_{2} = \pi$$
Numerical solution$$t_{1} = -43.9822971502571$$
$$t_{2} = -31.4159265358979$$
$$t_{3} = 84.8230016469244$$
$$t_{4} = -91.106186954104$$
$$t_{5} = -97.3893722612836$$
$$t_{6} = 91.106186954104$$
$$t_{7} = 6.28318530717959$$
$$t_{8} = -72.2566310325652$$
$$t_{9} = -47.1238898038469$$
$$t_{10} = -113.097335529233$$
$$t_{11} = 94.2477796076938$$
$$t_{12} = 50.2654824574367$$
$$t_{13} = 56.5486677646163$$
$$t_{14} = 43.9822971502571$$
$$t_{15} = 47.1238898038469$$
$$t_{16} = -50.2654824574367$$
$$t_{17} = 37.6991118430775$$
$$t_{18} = -28.2743338823081$$
$$t_{19} = 65.9734457253857$$
$$t_{20} = 15.707963267949$$
$$t_{21} = 28.2743338823081$$
$$t_{22} = -62.8318530717959$$
$$t_{23} = 40.8407044966673$$
$$t_{24} = -40.8407044966673$$
$$t_{25} = -6.28318530717959$$
$$t_{26} = -81.6814089933346$$
$$t_{27} = -15.707963267949$$
$$t_{28} = -59.6902604182061$$
$$t_{29} = 72.2566310325652$$
$$t_{30} = 3.14159265358979$$
$$t_{31} = -25.1327412287183$$
$$t_{32} = 21.9911485751286$$
$$t_{33} = -75.398223686155$$
$$t_{34} = -56.5486677646163$$
$$t_{35} = -267.035375555132$$
$$t_{36} = -69.1150383789755$$
$$t_{37} = -84.8230016469244$$
$$t_{38} = 78.5398163397448$$
$$t_{39} = 9.42477796076938$$
$$t_{40} = -232.477856365645$$
$$t_{41} = -53.4070751110265$$
$$t_{42} = 62.8318530717959$$
$$t_{43} = -18.8495559215388$$
$$t_{44} = 25.1327412287183$$
$$t_{45} = 100.530964914873$$
$$t_{46} = -87.9645943005142$$
$$t_{47} = -9.42477796076938$$
$$t_{48} = 75.398223686155$$
$$t_{49} = 81.6814089933346$$
$$t_{50} = 87.9645943005142$$
$$t_{51} = 12.5663706143592$$
$$t_{52} = -34.5575191894877$$
$$t_{53} = 69.1150383789755$$
$$t_{54} = -3.14159265358979$$
$$t_{55} = 0$$
$$t_{56} = -21.9911485751286$$
$$t_{57} = -37.6991118430775$$
$$t_{58} = 31.4159265358979$$
$$t_{59} = -78.5398163397448$$
$$t_{60} = -12.5663706143592$$
$$t_{61} = -94.2477796076938$$
$$t_{62} = 97.3893722612836$$
$$t_{63} = -100.530964914873$$
$$t_{64} = 59.6902604182061$$
$$t_{65} = 53.4070751110265$$
$$t_{66} = 34.5575191894877$$
$$t_{67} = -65.9734457253857$$
$$t_{68} = 18.8495559215388$$