ClearAll["Global`*"];

x=2;
y=6;

ClearAll[x,y]
Integrate[(x^2),x]

?=

x1=Integrate[Sin[(x^2)],x]

?x1

?:=

x2:=Integrate[Sin[(x^2)],x]

?x2

FullForm[Hold[u=v]]

ClearAll[f1]
f1[x:_]:=x*Tanh[10Sin[x]]
f1[5]

ClearAll[f1]
f1[x_]:=x*Tanh[10Sin[x]]
f1[5]

ClearAll[f2]
f2[x_,y_]:=x*Tanh[10Sin[y]]
f2[Pi,E]

f[x]:=x*Tanh[10Sin[x]]
f[1]

ClearAll[f1]
f1[x_]:=x*Tanh[10Sin[x]]
?f1

ClearAll[f3,x]

f3[x_]=Integrate[Sin[(x^2)],x];
f3[5.]

ClearAll[f4,x]

f4[x_]:=Integrate[Sin[(x^2)],x];
f4[5.]

ClearAll[a];
a[n_]:=1.*n*a[n-1];
a[0]:=1;
?a

Trace[a[3]]

$RecursionLimit=5000;
Timing[a[3500]]

ClearAll[a];
a[n_]:=a[n]=1.*n*a[n-1];
a[0]:=1;
a[8];
Trace[a[10]]

ClearAll[f5]
f5[1,1]:="odchazim";
f5[x_,y_]:=x+y;
f5[x_,4]:=(x^2);
f5[{x_,y_}]:="nechci te";
f5[s,2]
f5[10,4]
f5[{10,4}]
f5[1,1]

(*Listy*)
ClearAll["Global`*"];

?List

list1={a,b,c,10,{4,5}};
list2={a,b,c}={2,6,4};

list2[[3]]
list2[[-1]]
list2[[4]]

??List

Table[opice,{12}]

Table[(x^i),{i,12}]

Table[(x^i),{i,3,12}]

Table[(x^i),{i,3,12,2}]

n=4;
mat=Table[(E^i)+(Pi^j),{i,n},{j,i}]

n=4;
mat=Table[(E^i)+(Pi^j),{i,n},{j,4}]

MatrixForm[mat]

mf=MatrixForm;

mat//mf

Grid[mat,Frame->All]

?->

?/.

{ucitel,jeptiska,bleska}/.ucitel->ja

x/.{x->1}

x/.{{x->1}}

x/.{{x->1},{x->2}}

dosedZaIksy

dosadZaIksy=Solve[(x^2)+5x-6==0]
4*(x^3)-5/.dosadZaIksy[[1]]
4*(x^3)-5/.dosadZaIksy[[2]]

n=4;
mat=Table[(E^i)+(Pi^j),{i,n},{j,4}]

mat/.Plus->Times

n=4;
mat=Table[((E^i)/(Pi^j)),{i,n},{j,4}]/.(E/(π^4))->pes

n=4;
mat=Table[((E^i)/(Pi^j)),{i,n},{j,4}]
mat/.((a_)/(b_)):>(b/a)

(π/E)//FullForm
((E^3)/(π^3))//FullForm

n=4;
mat=Table[((j^2)/(2^3)),{i,n},{j,4}]
mat/.((a_)/(b_)):>(b/a)

dosx[[1,1]][[2]]

dosx[[1,1,2]]

Abs[Plus@@(x/.Solve[(1+(t^2))*(x^2)+t*x-4==0,x])]

rce=(1+(t^2))*(x^2)+t*x-4==0;
dosx=Solve[rce,x];
x1=x/.dosx[[1]];
x2=x/.dosx[[2]];
Plot[Abs[x1+x2],{t,0,6Pi}]