x <- seq(0, 30, 0.01)
plot(besselJ(x, 0), col = 2, type = "l",lwd = 2, ylab = "Jn(x)", xlab = "frecuencia(Hertz")
legend(x = 1900,y=0.8,         # Posición
       legend = c("J0", "J2"), # Textos de la leyenda
       lty = c(1, 2),          # Tipos de línea
       col = c(2, 3),          # Colores
       lwd = 2)