Plot[{Sin[E^x],  Cos[x]},  {x,  0,  Pi/2}]

FindRoot[Sin[E^x] == Cos[x],  {x,  1}]

Display["file.eps", %%, "EPS"]

Display["file.eps", 
      Plot[{Sin[E^x],  Cos[x]},  {x,  0,  Pi/2}], "EPS"]

Solve[x == 1/(1 - x),  x]

Re[x /. %] + I Im[x /. %]

TeXForm[x == 1/(1 - x)]

TeXForm[Sin[x]^2 + Cos[x]^2 == 1]

Plot3D[
      Sqrt[1 - x^2 - y^2],  {x,  -1,  1},  {y,  -1,  
        1}]

Plot3D[{-Sqrt[1 - x^2 - y^2],  
        Sqrt[1 - x^2 - y^2]},  {x,  -1,  1},  {y,  -1,  1},  
      PlotPoints -> 20]

ParametricPlot3D[{Cos[u] Cos[v],  Cos[u] Sin[v],  
        Sin[u]},  {u,  -Pi,  Pi},  {v,  -Pi/2,  
        Pi/2}]

d = 1

v := {I^I,  Pi^Pi^I,  2.1^2,  -3,  -3.0,  
        d}

d = 0.1

v d

Re[v]

Round[Re[v]]

D[Integrate[Cos[x],  x],  {x,  1}]

D[E^x,  x]

D[0,  x]

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

Plot[{Log[x E^x],  Log[x] + x},  {x,  E^(-1),  
        E^E}]

FullSimplify[Log[x] + x]

FullSimplify[Log[x E^x]]

Assuming[x > 0, FullSimplify[Log[E^x x]]]

Solve[a x^2 + b x + c == 0,  x]

Solve[x^3 - a^3 == 0,  x]

Solve[a x^4 + b x^2 + c == 0,  x]

Sqrt[x^(-2/3) + 1]

Head[%]

FullForm[%%]

Power[Plus[1, Power[x, Rational[-2, 3]]], 
          Rational[1, 2]]

2^2^5 + 1

FactorInteger[%]