1+1
2+3

a=2;
b=a+3;

b

d=(b^2)

(5^3)

(5/7)

(Sqrt[2])

Sin[π]

Sin[5]

Sin[5.]

N[Pi]

N[Pi,100]

N[Pi]
Pi//N
N@Pi

kyncl*is*stupid*guy

12ape

ape12

?=

x=3

ClearAll[x]
Limit[(((E^(2x))-1)/(Sin[x])),x->0]

DSolve[y''[x]+2y[x]==0,y[x],x]

Integrate[((Sin[(x^2)])/(Sqrt[x])),x]

?_

??__

?___

ClearAll[f];
f[x:_]:=(x^2);
f[x]

?:=

ClearAll[f];
f[x_]:=1+1
?f
f[5]

?=

ClearAll[f];
f[x_]=1+1
?f

ClearAll[f];
x=5;
f[x_]:=x;
f["Prague"]

ClearAll[f];
x=5;
f[x_]=x;
f["Prague"]
?f

ClearAll[f];
f:=Random[]
{f,f,f,f,f,f}

ClearAll[f];
f=Random[]
{f,f,f,f,f,f}

ClearAll[f,x]
f[x_]:=∫Sin[x]\[DifferentialD]x
f[5]

ClearAll[f,x]

f[x_]=∫Sin[x]\[DifferentialD]x
f[5]

ClearAll[f];
f[x_]:=1+x;
f[1]:=7;
f[x_,y_]:=(x^y);
f[4,y_]:=(y^2);
f[{a_,b_}]:={b,a};
f[{1,5}]

$RecursionLimit=(10^6);
ClearAll[a];
a[n_]:=n*a[n-1];
a[0]:=1;
Trace[a[3]];
Timing[Table[a[i],{i,1050}]][[1]]

ClearAll[a];
a[n_]:=a[n]=n*a[n-1];
a[0]:=1;
Trace[a[3]];
Timing[Table[a[i],{i,1850}]][[1]]

ClearAll[a];
a[n_]:=a[n]=n*a[n-1];
a[0]:=1;
a[5]
Trace[a[6]]

?/;

ClearAll[f];
f[x_]:=1-(x^2)/;-1<x≤1;
f[x_]:=f[x-2]/;x>1;
f[x_]:=f[x+2]/;x≤1;
(*Plot[f[x],{x,-5,5}]*)
Trace[f[4.56]];

ClearAll[f,z,y];
f[x_]:=Module[{y,z,w},
y=(Sqrt[x]);
z=(∫_1^y)Sin[t+x]\[DifferentialD]t;
w
];
f[2]

ClearAll[f];
f[x_]:=(x^2);
f[5]

((#)^2)&[5]

test[-5]

test[x_]:=x>2;
Select[{1,2,4,7,6,2},test]

Select[{1,2,4,7,6,2},#>2&]

t:=((#1)^2)-#2&
t[Pi,E]

Options[Plot]

Plot[Sin[x],{x,0,6Pi},AlignmentPoint->Center,AspectRatio->(1/GoldenRatio),Axes->True,AxesLabel->None,AxesOrigin->Automatic,AxesStyle->{},Background->None,BaselinePosition->Automatic,BaseStyle->{},ClippingStyle->None,ColorFunction->Automatic,ColorFunctionScaling->True,ColorOutput->Automatic,ContentSelectable->Automatic,CoordinatesToolOptions->Automatic,DisplayFunction:>$DisplayFunction,Epilog->{},Evaluated->Automatic,EvaluationMonitor->None,Exclusions->Automatic,ExclusionsStyle->None,Filling->None,FillingStyle->Automatic,FormatType:>TraditionalForm,Frame->False,FrameLabel->None,FrameStyle->{},FrameTicks->Automatic,FrameTicksStyle->{},GridLines->None,GridLinesStyle->{},ImageMargins->0.`,ImagePadding->All,ImageSize->Automatic,ImageSizeRaw->Automatic,LabelStyle->{},MaxRecursion->Automatic,Mesh->None,MeshFunctions->{#1&},MeshShading->None,MeshStyle->Automatic,Method->Automatic,PerformanceGoal:>$PerformanceGoal,PlotLabel->None,PlotLabels->None,PlotLegends->None,PlotPoints->Automatic,PlotRange->{Full,Automatic},PlotRangeClipping->True,PlotRangePadding->Automatic,PlotRegion->Automatic,PlotStyle->Automatic,PlotTheme:>$PlotTheme,PreserveImageOptions->Automatic,Prolog->{},RegionFunction->(True&),RotateLabel->True,TargetUnits->Automatic,Ticks->Automatic,TicksStyle->{},WorkingPrecision->MachinePrecision]

x=10!;
Plot[Sin[x],{x,0,6Pi},AxesLabel->{"x","Sin[x]"}];