# Apri R, "SELEZIONA TUTTO" e "COPIA"
tic <- function(x) {sec <-proc.time()[3]; while(proc.time()[3] < sec+x) sec <- sec}
f <- function(x) sqrt(1-(x^2)); n <- 300; for(i in 0:n*0.8) {tic(0.02);plot(f,-1,1,asp=1);
x <- -1+2/n*i; lines(c(-1,x,1,-1),c(0,f(x),0,0),col="blue"); points(x*0.9,f(x)*0.9)}
text(0,0.9,"Quanto è ampio"); text(0,0.82,"l'angolo evidenziato?")
tic(3)
x <- y <- seq(-10, 10, 0.5)
f <- function(x,y) { r <- sqrt(x^2+y^2); 10 * sin(r)/r }
z <- outer(x, y, f)
for(t in 0:100) persp(x,y,z, theta=30+t/2, phi=t/2, expand=1/2, col="lightblue")
tic(3)
tic <- function(x) {sec <- proc.time()[3]; while(proc.time()[3] < sec+x) sec <- sec} # passano x sec
plot(c(0,10),c(0,10),type="n",xlab="",ylab="")
text(5,6,"E' un'ELLISSE o una PARABOLA ?"); text(5,4,"Osserva l'animazione e rispondi")
tic(4); n <- 200; i <-0; for (k in 0:n) {tic(0.1);x <- c(0,10); y <- c(0,10);
{z <- array(c(0,0,0,0),dim=c(2,2))};
{pr <- persp(x,y,z,xlim=c(0,10),ylim=c(0,10),zlim=c(0,10),phi=0+i,theta=-30)};
{x <-seq(-20,30,length=200);lines(trans3d(x,z=0,y=(x-5)^2,pmat=pr),col="red");i <-i+40/n}}
tic(2); i <-0; for (k in 0:n) {tic(0.03);x <- c(0,10); y <- c(0,10);
{z <- array(c(0,0,0,0),dim=c(2,2))};
{pr <- persp(x,y,z,xlim=c(0,10),ylim=c(0,10),zlim=c(0,10),phi=40-i,theta=-30)};
{x <-seq(-20,30,length=200);lines(trans3d(x,z=0,y=(x-5)^2,pmat=pr),col="red");i <-i+40/n}}
tic(3)
for (k in 1:8) {tot <- 20*k^3; x <- vector(length=tot); tic(0.2);
for (i in 1:tot) {x[i] <- 0; for(j in 1:12) x[i] <- x[i]+floor(runif(1)*6)+1};  
hist(x,seq(11.5,72.5,1),right=FALSE,xlab="",main="",freq=FALSE,col="yellow")}
text(23,0.06,"lancio di 12 dadi"); text(23,0.052,"equi 10 mila volte")