Maths doubt

Posted by Noel on Apr 10, 2014; 6:34pm
URL: http://discussion-forum.276.s1.nabble.com/Maths-doubt-tp7586601.html

A rectangle has its lower left hand corner at the origin and its upper right hand corner on the graph of f(x)=x^2+x^(-2).For which x is the area of the rectangle minimised?
a. x=0
b. x=infinity
c. x=(1/3)^(1/4)
d. x=2^(1/3)