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Numerical Ability
Quadratic Equations
Q. If x = 3 + 3^1/2, then what is the value of x^2 + 9/x^2?
Read Solution (Total 12)
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- Given x=3+3^1/2 x^2=9+3+2(3)(3^1/2)=12+6(3)^1/2
1/x=1/(3+3^1/2
to find x^2 + 9/x^2=12+6(3)^1/2+(((12-6(3)^1/2)/36)*9=15+9/2(3)^1/2 - 11 years agoHelpfull: Yes(14) No(5)
- 1/x => (3-√3)/3,
x^2 => 12+6√3,
x^2+9/x^2 => [x^2+(3/x)^2+{2*x+(3/x)}]-{2*x*(3/x)}
=> {(x+3/x)^2-6}
=> {(3+√3)+3*(3-√3)/3}^2-6
=> (3+√3+3-√3)^2-6
=> 36-6 => 30 Ans. - 11 years agoHelpfull: Yes(5) No(24)
- Isn't correct
x = 3 + 3^(1/2) = 3 + 1.732 = 4.732
then
( (4.732)^4 + 9 ) / (4.732)^2
results : 22.79375642 - 10 years agoHelpfull: Yes(5) No(2)
- hi krishna pls explain x^2 + 9/x^2=12+6(3)^1/2+(((12-6(3)^1/2)/36)*9=15+9/2(3)^1/2
- 10 years agoHelpfull: Yes(2) No(1)
- (x-3)^2=3
x-3=root3
x^2+9-6x=3
x^4+9x^2=3x^2+6x^3
(x^4+9x^2)/x^2=3+6x
(x^2+9/x^2)=3+6(3+root3)=21+6*root3 - 10 years agoHelpfull: Yes(1) No(3)
- first up-whole we find the value of X.
so, X=3+3^1/2=3+1.3=4.5
THEN x^2+9/x^2 =4.5^2+9/4.5^2= 20.25+9/20.25
20.25*20.25+9/20.25=419.0625/20.25= 20.9
- 10 years agoHelpfull: Yes(1) No(1)
- 1/x => (3-√3)/3,
x^2 => 12+6√3,
x^2+9/x^2 => [x^2+(3/x)^2+{2*x+(3/x)}]-{2*x*(3/x)}
=> {(x+3/x)^2-6}
=> {(3+√3)+3*(3-√3)/3}^2-6
=> (3+√3+3-√3)^2-6
=> 36-6 =>30 - 10 years agoHelpfull: Yes(0) No(3)
- after substituting x value in eqn we get,
x^2+9/x^2= -((3+3^1/2))/2
= -x/2
ans is -x/2.
- 10 years agoHelpfull: Yes(0) No(1)
- @DSS SUNEEL , (x^4+9x^2)/x^2 gives (x^2+9) but not (x^2+9/x^2)
- 10 years agoHelpfull: Yes(0) No(0)
- x^2=(3+3^1/2)^2=3^2+3=12
so 12+9/12=51/4 - 10 years agoHelpfull: Yes(0) No(2)
- x=3+3^1/2 ==>x=3+3/2 ==>x=6/2 ==> x=3
x^2+9/x^2 ==>3^2+9/3^2 = 9+9/9 = 18/9 =2 - 10 years agoHelpfull: Yes(0) No(2)
- x=3+3^1/2,1/x=3-3^1/2
so answer is 5.6848 - 10 years agoHelpfull: Yes(0) No(1)
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