A real-valued function f defined for nonzero real numbers satisties f(1/x)+1/xf(-x) = 2x. What is the value of f(2)?
f(1x)+1xf(−x)=2x ;now let x→−1xf(−x)−xf(1x)=−2x ;and multiply by 1x1xf(−x)−f(1x)=−2x2
now add this to the original equation 2xf(−x)=2x−2x2=2x3−2x2f(−x)=x3−1x=x2−1xf(x)=x2+1x
f(2)=22+12=92