x+(1/x) = 2.5 find x^2 + (1/x^2)

• 4.25
  
  squaring on both sides (x+1/x)^2=2.5^2
  x^2+1/X^2=6.25-2
  x^2+1/X^2=4.25
• 13 years agoHelpfull: Yes(11) No(1)
• x^2+1/x^2=(x+1/x)^2-2*x*1/x=(2.5)^2-2[2.5 value is given]=6.25-2=4.25..ans is 4.25.
  This is based on this formula a^2+b^2=(a+b)^2-2*a*b
• 10 years agoHelpfull: Yes(1) No(0)
• x+ (1/x)=2.5
  x^2+ (1/x^2) +2= 5 (squaring both sides)
  x^2 +(1/x^2)=3
• 12 years agoHelpfull: Yes(0) No(6)