1+1

x = 1.0;

y = x;

z:=x;

Print[x]

Print[y]

Print[z]

x = 2.0;

Print[x]

Print[y]

Print[z]

Hold[FullForm[x = 1]]

Hold[FullForm[z:=x]]

Clear[x , y , z]

{x , y , z} = {1.0 , 2.0 , 3.0};

Print[{x , y , z}]

Hold[FullForm[{x , y , z} = {1.0 , 2.0 , 3.0}]]

FullForm[{1.0 , 2.0 , 3.0}]

Hold[FullForm[{1.0 , 2.0 , 3.0}]]

Clear[x , y , z]

Factorial[3]

3!

Hold[FullForm[3!]]

Factorial[0]

silnia[0] = 1;

silnia[n_]:=silnia[n -1] n;

silnia[1]

silnia[2]

silnia[3]

silnia[10]

Factorial[10]

FullSimplify[1 + 2 x + (x^2)]

(*to jest komentarz*)

(*ctrl + 6*)

(((1 + x))^2)

Hold[FullForm[(((1 + x))^2)]]

Power[1 + x , 2]

(*- + >*)

FullSimplify[x + 2 >0 ,Assumptions-> x>0]

f[x_ , y_]:=If[(x^2) + (y^2)<(0.75^2),True,False];

f[0.1 , 0.3]

f[1.1 , 2.2]

RegionPlot[f[x , y] , {x , -1 , 1} , {y , -1 , 1}]

covidData = Import["https://github.com/CSSEGISandData/COVID-19/raw/master/csse_covid_19_data/csse_covid_19_time_series/time_series_covid19_confirmed_global.csv"];

covidData//TableForm

covidData//Dimensions

covidData[[1]];

covidData[[2;;]];

covidData[[3,1;;4]]

ListPlot[covidData[[3,5;;]]]

{1 , 2 , 3 , 4}[[-2;;]]