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Kalpit Sing
Asked: 2022-11-10T10:57:45+05:30 In:

If a,b and c also represent the sides of a triangle and a,b,c are in g.p then the complete set of `alpha^2 = (r^2 +r +1)/(r^2-r+1)`is
A. `(1/3,3)`
B. (2,3)
C. `[1/3,2]`
D. `(sqrt(5+3)/2,3)`

If a,b and c also represent the sides of a triangle and a,b,c are in g.p then the complete set of `alpha^2 = (r^2 +r +1)/(r^2-r+1)`is
A. `(1/3,3)`
B. (2,3)
C. `[1/3,2]`
D. `(sqrt(5+3)/2,3)`
Parabola
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  1. Correct Answer – D
    Let b=ar,c=`ar^(2)andrgt0`
    As the sum of two sides is more than the third side, we have
    `rin((sqrt5-1)/2,(sqrt5+1)/2)` – {1}
    `rArrr+1/r-1in(1,sqrt5-1)`
    As `alpha^(2)=(r^(2)+r+1)/(r^(2)-r+1)=1+2/(r+1/r-1)`
    `thereforealpha^(2)in((sqrt5+3)/2,3)`

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