SOLUTION: if x is a positive real number, show thata x+(4/x)>=4. When does equality hold?

Algebra ->  Algebra  -> Quadratic Equations and Parabolas  -> Quadratic Equation Customizable Word Problems -> SOLUTION: if x is a positive real number, show thata x+(4/x)>=4. When does equality hold?      Log On

Ad: You enter your algebra equation or inequality - Algebrator solves it step-by-step while providing clear explanations. Free on-line demo .
Ad: Algebrator™ solves your algebra problems and provides step-by-step explanations!
Ad: Algebra Solved!™: algebra software solves algebra homework problems with step-by-step help!

   

Question 26171: if x is a positive real number, show thata x+(4/x)>=4. When does equality hold?
Answer by venugopalramana(3286) About Me  (Show Source):
You can put this solution on YOUR website!
if x is a positive real number, show thata x+(4/x)>=4. When does equality hold?
LET Y=X+4/X-4
Y=(X^2+4-4X)/X
=(X-2)^/X
N.R. BEING A PERFECT SQUARE IS ALWAYS POSITIVE.X IS GIVEN TO BE POSITIVE.HENCE Y IS POSITIVE.ITS MINIMUM VALUE WOULD BE ZERO WHEN X=2
THAT IS X+4/X=MINIMUM VALUE OF 4 WHEN X=2