{Slider[Dynamic[x],{0,1}],Dynamic[x]}

Manipulate[(2x)^2 + 1,{x,0,1}]

Manipulate[Plot[(2y)^2 + x, {y, -1, 1}, PlotRange -> {-0.5, 3}],{x,0,1}]

Type Plot[x^2,{x,0,1},PlotStyle->RGBColor[0.494118, 0.0784314, 0.00392157]]

f[x_]:=Mod[x,4]==1&&PrimeQ[x];list=Range[100];Select[list,f]

Plot3D[Sin[x*y],{x,-2,2},{y,-2,2},RegionFunction->Function[{x,y},1<x^2+y^2<4]]

One way to create TraditionalForm input: Type e.g. Integrate[Sin[x], {x, 0, 1}], select it, and press Ctrl+Shift+T

Clear[x]
(∫_0^1)sin(x)\[DifferentialD]x

Plot[{Exp[x],Sin[x]},{x,0,2},Filling->{1->{2}}]

Plot with custom mesh divisions: http://t.co/B5ACoKyp

Plot3D[x^2 y^3,{x,-3,3},{y,-3,3},MeshFunctions->{#3&},MeshShading->{Yellow,None}]

Ctrl+‘ (Mac: Cmd+‘) opens/closes a cell group. Examples: In a Section cell, it closes the section. In an input cell, it hides the output.  Peeter: not clear what this is about (what does open/close mean here?)

Expected smallest value of 3 samples from a normal distribution: . http://j.mp/tXP40D

Mean[OrderDistribution[{NormalDistribution[], 3}, 1]]

-(3/(2 (Sqrt[π])))
{NormalDistribution[], 3}

{NormalDistribution[0,1], 3}

Ten uniformly random numbers:
RandomReal[{0,1},10]

.Ten Poisson-distributed random integers:.

RandomVariate[PoissonDistribution[3],10]

5 dimensional array:.Transpose the 2nd and 5th dimensions:.http://j.mp/uiVogc

a=RandomReal[1,{2,2,2,2,2}]

Transpose[a,{1,5,3,4,2}]

MathematicaTip:Fit model parameters to data:.http://t.co/bmqk4ZSC

Clear[x, a, b]
NonlinearModelFit[{{0,1},{1,0},{3,2},{5,4},{6,4},{7,5}},Log[a+b*x^2],{a,b},x]

Plot[ Log[1.5063204891556878 +1.4263297975161129 (x^2)], {x, 0, 10}]
Clear[t]
t := {{0,1},{1,0},{3,2},{5,4},{6,4},{7,5}}
ListPlot[t]