El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\frac{\frac{\sin{\left(5 x \right)}}{1000} + \frac{\cos{\left(5 x \right)}}{50}}{e^{\frac{1}{4}}} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = - \frac{\operatorname{atan}{\left(20 \right)}}{5}$$
Solución numérica$$x_{1} = -19.7820420384713$$
$$x_{2} = -7.84398995483009$$
$$x_{3} = -17.8970864463174$$
$$x_{4} = 49.9613148712221$$
$$x_{5} = 34.2533516032731$$
$$x_{6} = -63.7643391887284$$
$$x_{7} = -58.1094724122668$$
$$x_{8} = -32.3484126528305$$
$$x_{9} = 58.1294557705556$$
$$x_{10} = 16.0321142124523$$
$$x_{11} = 32.3683960111193$$
$$x_{12} = 92.0586564293253$$
$$x_{13} = -80.1006209873953$$
$$x_{14} = -70.047524495908$$
$$x_{15} = 284.324126829021$$
$$x_{16} = 71.9524634463506$$
$$x_{17} = -83.8705321717031$$
$$x_{18} = -92.0386730710366$$
$$x_{19} = -38.0032794292921$$
$$x_{20} = -11.6139011391378$$
$$x_{21} = 48.0763592790682$$
$$x_{22} = 50.5896334019401$$
$$x_{23} = -4.07407877052234$$
$$x_{24} = -59.9944280044207$$
$$x_{25} = -43.6581462057537$$
$$x_{26} = -98.9501769089341$$
$$x_{27} = 54.3595445862478$$
$$x_{28} = 5.979017720965$$
$$x_{29} = -53.7112426972411$$
$$x_{30} = 82.005559937838$$
$$x_{31} = 24.2002551117858$$
$$x_{32} = 76.3506931613764$$
$$x_{33} = 39.9082183797348$$
$$x_{34} = -65.6492947808823$$
$$x_{35} = -46.7997388593435$$
$$x_{36} = -95.8085842553443$$
$$x_{37} = 2.20910653665724$$
$$x_{38} = -54.339561227959$$
$$x_{39} = 12.2622030281446$$
$$x_{40} = 46.1914036869143$$
$$x_{41} = 4.09406212881112$$
$$x_{42} = 0.324150944503368$$
$$x_{43} = -85.755487763857$$
$$x_{44} = -31.7200941221125$$
$$x_{45} = -39.888235021446$$
$$x_{46} = -49.9413315129333$$
$$x_{47} = 68.1825522620429$$
$$x_{48} = 27.3418477653756$$
$$x_{49} = 83.8905155299919$$
$$x_{50} = 14.1471586202985$$
$$x_{51} = -27.9501829378048$$
$$x_{52} = 70.0675078541968$$
$$x_{53} = 78.2356487535302$$
$$x_{54} = -29.8351385299586$$
$$x_{55} = -87.6404433560108$$
$$x_{56} = 90.1737008371715$$
$$x_{57} = 27.9701662960935$$
$$x_{58} = 26.0852107039397$$
$$x_{59} = -26.0652273456509$$
$$x_{60} = 22.3152995196319$$
$$x_{61} = 95.2002490829151$$
$$x_{62} = -48.0563759207794$$
$$x_{63} = 98.3418417365049$$
$$x_{64} = 36.138307195427$$
$$x_{65} = 66.297596669889$$
$$x_{66} = 87.6604267142996$$
$$x_{67} = -41.7731906135999$$
$$x_{68} = 88.2887452450176$$
$$x_{69} = 44.3064480947605$$
$$x_{70} = -61.8793835965745$$
$$x_{71} = 80.1206043456841$$
$$x_{72} = 7.86397331311887$$
$$x_{73} = 43.0498110333246$$
$$x_{74} = 10.3772474359907$$
$$x_{75} = -21.6669976306252$$
$$x_{76} = -51.8262871050872$$
$$x_{77} = 60.0144113627094$$
$$x_{78} = -93.9236286631904$$
$$x_{79} = -75.7023912723696$$
$$x_{80} = -16.0121308541636$$
$$x_{81} = -73.8174356802158$$
$$x_{82} = 61.8993669548633$$
$$x_{83} = 93.3152934907612$$
$$x_{84} = 17.9170698046062$$
$$x_{85} = -67.5342503730362$$
$$x_{86} = -19642.1697563603$$
$$x_{87} = -89.5253989481647$$
$$x_{88} = -9.72894554698397$$
$$x_{89} = -97.6935398474982$$
$$x_{90} = -81.9855765795492$$
$$x_{91} = 38.0232627875809$$
$$x_{92} = -14.1271752620097$$
$$x_{93} = -71.9324800880619$$
$$x_{94} = 93.9436120214792$$
$$x_{95} = 100.226797328659$$
$$x_{96} = -36.1183238371382$$
$$x_{97} = 56.2445001784017$$
$$x_{98} = -5.95903436267622$$