Problem
First name
Johnny Cubbon
School
St Paul's juniors
Country
Age
13
Email address
johnnycubbon@icloud.com
Question: x^1/2+(1/x^1/2)<4. Find the ranges of x.
(x/x^1/2)+(1/x^1/2)<4
x+1/x^1/2<4
x+1<4(x^1/2)
Square both sides: (x+1)^2<16x
x^2+2x+1<16x
x^2-14x+1<0
If x^2-14x+1=0, we can find a range of values of x.
Using the quadratic formula- x= [14+(14^2-(4)(1)(1))^1/2]/2
x=(14+192^1/2)/2
=7+48^1/2
Answer: 0<(less than or equal to) x < 7+48^1\2
Side note: x must be positive as it is square rooted.