!"#! & '! (& )* $% &! & + ' !& , + -!& # !. % & = + = * θ = θ = π, / + #"% (& = +π , /& * = *0 θ = π & = 0θ = π ,* & + − = + π , *& = + + &* * = = + + &+ − & * + π , *& + + &,+ − & = * π −* = * # # + & 1+*& # !. % θ0 = = 3 3 3 + & +*& − = 3 3 + 5+ [ − − − [ ϕ2 = θ + θ& + ϕ + ϕ& θ ϕ− θ ϕ + + θ +θ + ϕ & + +θ + ϕ &] +θ + ϕ & θ ]− = + −θ & + * θ − * + −θ & − + θ + +−θ & * θ θ − θ& + ϕ + θ θ θ − θ& ϕ& 4 6 7 8 ! + − + &6 = + * + # !. % ∴+ * + * = + * * + 6π , /& *6 + 9π , / & +π , 6 & = 6 + /π , 6& 6 &/ = − − = + :π , / & * + = #; ! !. * * + 9π , /& + /π , 6 & / θ∈ + :π , /& * . # 0 = ! # !. % ! !! θ ∈ [?0 *π ] = & + 9 π , / + :π , / − /π , 6& = / 3 / = θ !; 0 = 0 θ = θ + θ + # !! . # θ ! ># !; θ (! θ& = 7 = * 6 + * θ 0 ( ∈ 0 + π , <& ( θ 0 = + % $ ∴ + − + &6 = * # / !( − + $ ⋅ +− − & 6 & * !"#! ? ! θ + ! ># − θ+ θ& + θ0 ∈ 0 ' −* * θ+ θ + + + − & * "# − −* θ − θ = − @! $ = * θ + θ& + * θ+ * 7 −6 % ! !( . # !. ! + & * * 6 θ θ !"# ($ 6 = + + & * * # !. % + & = # !. = # + * !. 6 = * 6?A0 ! " + π , 6& ! 0 !!; ! ! 0 θ + + − &+ − *& < * θ − θ θ θ 6 6θ = θ −6 θ 6θ = 6 * θ θ + θ + ; *θ = *θ = * + θ& − ( −* = ! =6 : θ + − & * θ θ ! "! ! θ = * θ = ' 3 * 0 !"# # θ 6 θ − ( < # B 6+ − # # !. % 6+ − ? = − + = * = * C + *π , 6& 0 # " = * 6 + *π , < & = * # % * < + * * * < + /π , 6& = − − * * +π , 6& = *π , 6 + *π = * * !D 0 B # ! " 0 ! ! + & = < + # !. % (! + =? < ># >#!; ( B +6π , < & = * = + :π , < & = − 6 + * * 6 = + Cπ , < & = − 6 − * * / = + 9π , < & = − : = + : / 0 &+ − ? 6 6 − * * !"# & ? ) * π , <& = + & = + − #! 6 + * * = # 7 !0 π0 − = +π , < & = ># + &0 # = ? + (0 #"0 & + − : & E # * # !. % ∈ ∈ ϕ = θ ϕ0 = ! !( & ! "! ! 0 ># ϕ = ϕ = +& +*& θ θ + & * + + *& * % #"0 = * ! F 0 θ θ 0 ># # # !. = = ?0 0 *0 (! "# − 0 ?∈ π + 8 @ 0 + & 1 +*& θ + * π 0 ∈ (! #! @! F !!># ># ϕ = θ + * π0 ∈ ! = % = * # ϕ = ϕ = ! ! $ ># . = ? # !. % π = # !. 1 + "# 9 ! ϕ ≠ ? = ! 0 + = π + = − + =? ! 0 !ϕ= ># ! + # ! 0 1># ! !! ! # BD )= ! θ + * π # !. 0 0 # !. ># ; 1 & G F !!># ># ∀ 0 ? +& +*& + *π = = ∈ + # !. % ! = ? 1, $ # = ?0 ? + *θ 0 " 0 = ( *θ 0 ># +& 3 + *π ! = *θ = = 0 ≠ ? 1 ># + % = + + + & = 0 + 2 #" ⋅ + ! 7 ! 1 & + + &++ + & + + &++ + & + + + *π & 3 3 3 + = + + *π & ! !! = + ! θ ∈ [ ? 0 *π ] ∈ # θ = 0 & ># + θ * θ = + ! ? & = &+ + 3 3 3 +*& ! * θ * # !. % = θ = # ># 0 ! ># 0 * 0 6 0 0 8 " !. " =! 2 #" = + − =? 80 ! − . # !( % !; θ = =? θ + + =? ! ! ( θ + θ& = + + &θ − + θ − + "# + + &θ − + ∈ ? 0 ># + + &θ θ !"# ! ( = " θ0 = + + &θ = ψ θ − + θ = ϕ # !"# % !. + # # ># = [ 3 *[ − = + − + + &θ − ]* + * + + &θ + θ * + + &θ ] = * θ − &* + * θ = +ψ − ϕ & 8# +ψ − ϕ & = − θ θ& = * *+ − 1# * !"# !"#! % + + &θ θ ψ + + &θ − ># (! % +ψ − ϕ & = −* * ∴ θ − + − − = * + −* θ * ⋅ + * θ * + θ * θ * * θ θ * + θ * * * * θ + * θ * 3 + θ * θ * * θ 0 1 ># * ⋅ θ * >? + θ * * * * θ + θ * θ + θ * θ * + θ * + θ *