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f-x-f-1-x-x-2-gt-f-x-




Question Number 191151 by TUN last updated on 19/Apr/23
f(x)+f(1−x)=x^2   =>f(x)=¿
f(x)+f(1x)=x2=>f(x)=¿
Answered by Rasheed.Sindhi last updated on 19/Apr/23
f(x)+f(1−x)=x^2 .......(i)  Replacing x by 1−x:  f(1−x)+f( 1−(1−x) )=(1−x)^2   f(1−x)+f( x )=(1−x)^2 ......(ii)  (i)   &   (ii): x^2 =(1−x)^2   x^2 =1−2x+x^2   1−2x=0⇒x=(1/2)  x is constant  f((1/2))+f(1−(1/2))=((1/2))^2 =(1/4)  2f((1/2))=(1/4)⇒ f((1/2))=(1/8)
f(x)+f(1x)=x2.(i)Replacingxby1x:f(1x)+f(1(1x))=(1x)2f(1x)+f(x)=(1x)2(ii)(i)&(ii):x2=(1x)2x2=12x+x212x=0x=12xisconstantf(12)+f(112)=(12)2=142f(12)=14f(12)=18
Commented by mr W last updated on 19/Apr/23
but in f(x)+f(1−x)=x^2  x is not a  constant but a variable (∈R).  so i think the answer is that  f(x) satisfying f(x)+f(1−x)=x^2    doesn′t exist.
butinf(x)+f(1x)=x2xisnotaconstantbutavariable(R).soithinktheansweristhatf(x)satisfyingf(x)+f(1x)=x2doesntexist.
Commented by Rasheed.Sindhi last updated on 19/Apr/23
Very right sir! Thanks!
Veryrightsir!Thanks!

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