Oi Elias,

Tenta o seguinte:

library(gridExtra)

library(lattice)

x <- seq(pi/4, 5 * pi, length.out = 100)

y <- seq(pi/4, 5 * pi, length.out = 100)

r <- as.vector(sqrt(outer(x^2, y^2, "+")))

grid <- expand.grid(x=x, y=y)

grid$z <- cos(r^2) * exp(-r/(pi^3))

plot1<-levelplot(seu plot)

plot2<-levelplot(seu outro plot)

grid.arrange(plot1,plot2)

Att,

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