Graph of the function intersects the axis X at f = 0
so we need to solve the equation:
$$\frac{\cos{\left(x \right)} \cos{\left(x \right)}}{\sin{\left(x \right)}} = 0$$
Solve this equationThe points of intersection with the axis X:
Analytical solution$$x_{1} = \frac{\pi}{2}$$
$$x_{2} = \frac{3 \pi}{2}$$
Numerical solution$$x_{1} = -76.969019142094$$
$$x_{2} = 42.4115007257482$$
$$x_{3} = -48.6946856519848$$
$$x_{4} = -26.7035384718653$$
$$x_{5} = 29.8451303260505$$
$$x_{6} = 23.5619451851288$$
$$x_{7} = 67.5442423466955$$
$$x_{8} = 45.553093765886$$
$$x_{9} = 10.9955752430018$$
$$x_{10} = -39.2699084457792$$
$$x_{11} = -51.8362786889097$$
$$x_{12} = -7.85398149471446$$
$$x_{13} = 70.6858344565908$$
$$x_{14} = 83.2522045003433$$
$$x_{15} = -45.5530935939383$$
$$x_{16} = 4.71238871530383$$
$$x_{17} = 51.836278906418$$
$$x_{18} = -29.8451300946099$$
$$x_{19} = 20.4203521458051$$
$$x_{20} = 80.1106131287292$$
$$x_{21} = 48.6946858762043$$
$$x_{22} = -20.4203519762382$$
$$x_{23} = 36.1283159260006$$
$$x_{24} = -36.1283154153854$$
$$x_{25} = -10.9955733545245$$
$$x_{26} = -58.1194639960073$$
$$x_{27} = -48.6946870685899$$
$$x_{28} = -67.5442421738335$$
$$x_{29} = 76.9690195630622$$
$$x_{30} = -54.9778705470218$$
$$x_{31} = -64.4026491374242$$
$$x_{32} = 58.1194643607763$$
$$x_{33} = -4.71238848455677$$
$$x_{34} = -86.3937977179549$$
$$x_{35} = -32.9867219511814$$
$$x_{36} = -14.1371668348422$$
$$x_{37} = -98.9601677364429$$
$$x_{38} = -1.57079643412171$$
$$x_{39} = 89.5353909275596$$
$$x_{40} = 17.2787587191641$$
$$x_{41} = 92.6769830369374$$
$$x_{42} = 1.57079660442153$$
$$x_{43} = -10.9955747699649$$
$$x_{44} = -70.6858342354489$$
$$x_{45} = -95.8185758679732$$
$$x_{46} = 61.2610572679436$$
$$x_{47} = 86.3937978856968$$
$$x_{48} = -54.9778719374446$$
$$x_{49} = -26.7035370683564$$
$$x_{50} = 7.85398174563321$$
$$x_{51} = -73.8274272796526$$
$$x_{52} = 73.8274274867432$$
$$x_{53} = 32.9867223968539$$
$$x_{54} = 39.2699086835855$$
$$x_{55} = -76.9690205214496$$
$$x_{56} = 14.1371671153205$$
$$x_{57} = 61.2610559072772$$
$$x_{58} = 98.960168145952$$
$$x_{59} = 54.9778709800313$$
$$x_{60} = -98.9601691056411$$
$$x_{61} = -4.71238987596373$$
$$x_{62} = 10.9955738135239$$
$$x_{63} = -32.9867233536188$$
$$x_{64} = -89.5353907537234$$
$$x_{65} = 76.9690210413954$$
$$x_{66} = 64.4026493057109$$
$$x_{67} = -42.4115005568527$$
$$x_{68} = 26.7035372957759$$
$$x_{69} = -92.676982818755$$
$$x_{70} = -61.2610570263942$$
$$x_{71} = 17.2787600994214$$
$$x_{72} = 39.2699073135637$$
$$x_{73} = -17.2787598652139$$
$$x_{74} = 32.9867238414546$$
$$x_{75} = 98.9601696430262$$
$$x_{76} = 83.2522058525039$$
$$x_{77} = -92.6769842647274$$
$$x_{78} = 95.8185760670326$$
$$x_{79} = -83.2522056070609$$
$$x_{80} = -80.1106125767207$$
$$x_{81} = 54.9778724408964$$
$$x_{82} = -70.6858356661912$$
$$x_{83} = -23.5619450140352$$