2+2

E^(I*Pi)

22/7

N[22/7]

Sqrt[2]

N[Sqrt[2]]

a = 22/7
b = Pi
N[(a-b)/b]

c = Sqrt[10]
N[(Sqrt[10] - Pi)/Pi, 4]

firstfive = {1,2,3,4,5}

firstfive[[5]]

firstfive[[2]] = Pi

firstfive

squares = Table[{firstfive[[i]], firstfive[[i]]^2}, {i, 1, 5}]

N[squares, 3]

TableForm[%]

TableForm[squares]

firstten = Table[{i, Sqrt[i]}, {i, 1, 10}]
TableForm[N[firstten, 3]]

N[E]

Plot[Sin[x],{x,0,2*Pi},PlotRange->{{-0.5*2*Pi,1.5*2*Pi},{-2,2}},AxesLabel->{"x","y"}]

Plot[Sin[x],{x,0,2*Pi},PlotRange->{-2,2}]

Plot[Sin[x],{x,0,2*Pi}]

Plot[Sin[x],{x,0,2*Pi},PlotRange->{{-0.5*2*Pi,1.5*2*Pi},{-2,2}},Frame->True,FrameLabel->{"phase","amplitude"}]

Plot3D[Cos[Sqrt[x^2 + y^2]]*Exp[-Sqrt[(x^2 + y^2)]/5], {x, -6*Pi, 6*Pi}, {y, -6*Pi, 6*Pi}, PlotPoints->{100,100}, PlotRange->All]

VectorPlot[{y,y}, {x, -5, 5}, {y, -5, 5}]

d = ListPlot[firstten]

d1 = Plot[Sqrt[x], {x, 0, 10}]

Show[ListPlot[firstten], Plot[Sqrt[x], {x, 0, 10}]]

Needs["ErrorBarPlots`"]
ftte = Table[{{firstten[[i, 1]], firstten[[i, 2]]}, ErrorBar[0.1]}, {i, 1, Length[firstten]}]
ErrorListPlot[ftte]

ftte2 = Table[{{firstten[[i, 1]], firstten[[i, 2]]}, ErrorBar[{-0.3, 0.1}, {-0.1, 0.5}]}, {i, 1, Length[firstten]}]
ErrorListPlot[ftte2]

data8 = Import["http://pmaweb.caltech.edu/~phy003/labs/Data1.txt", "Table"]

data9 = Rest[data8]

ListPlot[data9]