f(x)=1/4x次方+2,x1x2属于R,且x1+x2=1 求证f(x1)+f(x2)=1/2

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f(x)=1/4x次方+2,x1x2属于R,且x1+x2=1 求证f(x1)+f(x2)=1/2
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f(x)=1/4x次方+2,x1x2属于R,且x1+x2=1 求证f(x1)+f(x2)=1/2
f(x)=1/4x次方+2,x1x2属于R,且x1+x2=1 求证f(x1)+f(x2)=1/2

f(x)=1/4x次方+2,x1x2属于R,且x1+x2=1 求证f(x1)+f(x2)=1/2
x2=1-x1
f(x1)+f(x2)
=1/(4^x1+2)+1/[4^(1-x1)+2]
=1/(4^x1+2)+4^x1/(4+2*4^x1)
=2/(4+2*4^x1)+4^x1/(4+2*4^x1)
=(2+4^x1)/(4+2*4^x1)
=(2+4^x1)/[2(2+4^x1)]
=1/2