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Question Number 2362 by 123456 last updated on 18/Nov/15
f:C→C,(a,b)∈R^2 ,a<b  f(z−a)=f(b−z)sin ((zπ)/(b−a))  f(z)=z^2 ,ℜ(z)≥((a+b)/2)  f(z)=0,z=?
f:CC,(a,b)R2,a<bf(za)=f(bz)sinzπbaf(z)=z2,(z)a+b2f(z)=0,z=?
Commented by Rasheed Soomro last updated on 20/Nov/15
Let a=0 then b>0:  f(z−a)=f(b−z)sin ((zπ)/(b−a))⇒f(z)=f(b−z)sin ((zπ)/b)=0 if f(z)=0  ⇒f(b−z)=0 ∣{ sin ((zπ)/b)=0⇒((zπ)/b)=sin^(−1) 0⇒z=0}  f(z)=0⇒z=0 is one solution.  For a=0 and b>0       f(z)=f(b−z)sin ((zπ)/b).............(i)       f(b−z)=f(b−b−z^(−) )sin(((b−z)π)/b)                           =f(z)sin(((b−z)π)/b).......(ii)  From (i) and (ii)      f(z)=(f(z)sin(((b−z)π)/b))sin ((zπ)/b)      (sin(((b−z)π)/b))(sin ((zπ)/b))=1      (1/2){cos((((b−z)π)/b)−((zπ)/b))−cos((((b−z)π)/b)+((zπ)/b))}=1      (1/2){cos((((b−z−z)π)/b))−cos((((b−z+z)π)/b))}=1      cos((((b−2z)π)/b))−cos((π)=2      cos((((b−2z)π)/b))+1=2      cos((((b−2z)π)/b))=1     (((b−2z)π)/b)=cos^(−1) (1)=0     b−2z=0          z=(b/2)  Continue
Leta=0thenb>0:f(za)=f(bz)sinzπbaf(z)=f(bz)sinzπb=0iff(z)=0f(bz)=0{sinzπb=0zπb=sin10z=0}f(z)=0z=0isonesolution.Fora=0andb>0f(z)=f(bz)sinzπb.(i)f(bz)=f(bbz)sin(bz)πb=f(z)sin(bz)πb.(ii)From(i)and(ii)f(z)=(f(z)sin(bz)πb)sinzπb(sin(bz)πb)(sinzπb)=112{cos((bz)πbzπb)cos((bz)πb+zπb)}=112{cos((bzz)πb)cos((bz+z)πb)}=1cos((b2z)πb)cos((π)=2cos((b2z)πb)+1=2cos((b2z)πb)=1(b2z)πb=cos1(1)=0b2z=0z=b2Continue
Commented by Rasheed Soomro last updated on 20/Nov/15
The condition ℜ(z)≥((a+b)/2)  is only for f(z)=z^2   ?
Thecondition(z)a+b2isonlyforf(z)=z2?
Commented by Rasheed Soomro last updated on 21/Nov/15
When you write statement and condition on   one line it should mean that the condition is  only for that statement.For example the condition  ℜ(z)≥((a+b)/2) is only in case f(z)=z^2  :  f(z)=z^2 ,ℜ(z)≥((a+b)/2)  Similarly in the following you are asked for z when  f(z)=0.  :  f(z)=0,z=?  Am I Right?
Whenyouwritestatementandconditionononelineitshouldmeanthattheconditionisonlyforthatstatement.Forexamplethecondition(z)a+b2isonlyincasef(z)=z2:f(z)=z2,(z)a+b2Similarlyinthefollowingyouareaskedforzwhenf(z)=0.:f(z)=0,z=?AmIRight?
Answered by Rasheed Soomro last updated on 21/Nov/15
f:C→C,(a,b)∈R^2 ,a<b  f(z−a)=f(b−z)sin ((zπ)/(b−a))  f(z)=z^2 ,ℜ(z)≥((a+b)/2)  f(z)=0,z=?  −−−−−−−−−−−−−−−−−−−−−  f(z−a)=f(b−z)sin ((zπ)/(b−a)) is true for any real a,b with a<b  Let a=0,then b>0  f(z−a)=f(b−z)sin ((zπ)/(b−a))          ⇒f(z)=f(b−z)sin ((zπ)/b)            ⇒ f(b−z)=f(b−b−z^(−) )sin ((zπ)/b)                                   =f(z)sin ((zπ)/b)  f(z)=f(z)sin ((zπ)/b)sin ((zπ)/b)  f(z)−f(z)sin^2  ((zπ)/b)=0  f(z)(1−sin^2  ((zπ)/b))=0  f(z)(1−sin((zπ)/b))(1+sin((zπ)/b))=0  f(z)=0   ∣     sin((πz)/b) =1  ∣   sin ((πz)/b)=−1                    ∣  ((πz)/b)=sin^(−1) (1)  ∣  ((πz)/b)=sin^(−1) (−1)                    ∣ ((πz)/b)=(π/2)  ∣  ((πz)/b)=((3π)/2)                    ∣ z=(b/2)     ∣ z=((3b)/2)        for a=0 ,b>0                    ∣  ℜ(z)≥ ((a+b)/2)=((0+b)/2)                    ∣  (b/2)≥(b/2)      Condition satisfied for z=(b/2)                    ∣ ((3b)/2)≥(b/2)        as well as    for z=((3b)/2)  −−−−−−−−−−−−−  Let b=0 [a<0]  f(z−a)=f(b−z)sin ((zπ)/(b−a))  ⇒f(z−a)=f(−z)sin ((zπ)/(−a))  ⇒f(z−a)=−f(−z)sin ((zπ)/a)  f(−z) =−((f(z−a))/(sin ((zπ)/a)))          f(z−a)=f(−a−z^(−) )=−((f(a−z−a))/(sin (((a−z)π)/a)))                                           =−((f(−z))/(sin (((a−z)π)/a)))  f(−z) =−((−((f(−z))/(sin (((a−z)π)/a))))/(sin ((zπ)/a)))  f(−z)=((f(−z))/(sin (((a−z)π)/a).sin ((zπ)/a)))  f(−z)−((f(−z))/(sin (((a−z)π)/a).sin ((zπ)/a)))=0  f(−z)[1−(1/(sin (((a−z)π)/a).sin ((zπ)/a)))]=0  f(−z)=0  ∣  (1/(sin (((a−z)π)/a).sin ((zπ)/a)))=1                       ∣  sin (((a−z)π)/a).sin ((zπ)/a)=1                       ∣ (1/2){cos((((a−z−z)π)/a))−cos((((a−z+z)π)/a)}=1                       ∣ (1/2){cos((((a−2z)π)/a))−cos((((a)π)/a)}=1                       ∣ (1/2){cos((((a−2z)π)/a))−cos(π)}=1                       ∣ cos((((a−2z)π)/a))+1=2                       ∣ cos((((a−2z)π)/a))=1                       ∣   (((a−2z)π)/a)=cos^(−1) (1)=0                       ∣  a−2z=0⇒z=(a/2)     [Satisfy the condition ℜ(z)≥((a+b)/2)] [b=0
f:CC,(a,b)R2,a<bf(za)=f(bz)sinzπbaf(z)=z2,(z)a+b2f(z)=0,z=?f(za)=f(bz)sinzπbaistrueforanyreala,bwitha<bLeta=0,thenb>0f(za)=f(bz)sinzπbaf(z)=f(bz)sinzπbf(bz)=f(bbz)sinzπb=f(z)sinzπbf(z)=f(z)sinzπbsinzπbf(z)f(z)sin2zπb=0f(z)(1sin2zπb)=0f(z)(1sinzπb)(1+sinzπb)=0f(z)=0sinπzb=1sinπzb=1πzb=sin1(1)πzb=sin1(1)πzb=π2πzb=3π2z=b2z=3b2fora=0,b>0(z)a+b2=0+b2b2b2Conditionsatisfiedforz=b23b2b2aswellasforz=3b2Letb=0[a<0]f(za)=f(bz)sinzπbaf(za)=f(z)sinzπaf(za)=f(z)sinzπaf(z)=f(za)sinzπaf(za)=f(az)=f(aza)sin(az)πa=f(z)sin(az)πaf(z)=f(z)sin(az)πasinzπaf(z)=f(z)sin(az)πa.sinzπaf(z)f(z)sin(az)πa.sinzπa=0f(z)[11sin(az)πa.sinzπa]=0f(z)=01sin(az)πa.sinzπa=1sin(az)πa.sinzπa=112{cos((azz)πa)cos((az+z)πa}=112{cos((a2z)πa)cos((a)πa}=112{cos((a2z)πa)cos(π)}=1cos((a2z)πa)+1=2cos((a2z)πa)=1(a2z)πa=cos1(1)=0a2z=0z=a2[Satisfythecondition(z)a+b2][b=0
Commented by Rasheed Soomro last updated on 21/Nov/15
This is not full answer.It is for a=0 or b=0 and also  z is pure real.  Needs verification  and  attestation.
Thisisnotfullanswer.Itisfora=0orb=0andalsozispurereal.Needsverificationandattestation.
Answered by Rasheed Soomro last updated on 22/Nov/15
f:C→C,(a,b)∈R^2 ,a<b  f(z−a)=f(b−z)sin ((zπ)/(b−a))  f(z)=z^2 ,ℜ(z)≥((a+b)/2)  f(z)=0,z=?  −−−−−−−−−−−−−−−−−−−−−  Let z=x+iy  f(z−a)=f(b−z)sin ((zπ)/(b−a))⇒f((x+iy)−a)=f(b−(x+iy))sin (((x+iy)π)/(b−a))  Let  b−a=1 then b=a+1    f((x+iy)−a)=f( a+1−(x+iy) )sin (x+iy)  Continue
f:CC,(a,b)R2,a<bf(za)=f(bz)sinzπbaf(z)=z2,(z)a+b2f(z)=0,z=?Letz=x+iyf(za)=f(bz)sinzπbaf((x+iy)a)=f(b(x+iy))sin(x+iy)πbaLetba=1thenb=a+1f((x+iy)a)=f(a+1(x+iy))sin(x+iy)Continue

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