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Given (2xsquared +1 )/xsquared minus 2x=k find the values of k for which real roots exist?
plz include the steps btw this question is worth 10 marks for sum reason
2 Answers
- AlekoLv 68 years agoFavorite Answer
(2x^2+1)/(x^2-2x)=k 2x^2+1=k(x^2-2x)
x^2(2-k)+2kx+1=0
for real roots the discriminant must be>0 so 4k^2-8+4k>0 (k+2)(k-1)>0
k>-2 and k>1
so there are real roots for values of k>1
- Iggy RockoLv 78 years ago
(2x^2 + 1)/(x^2 - 2x) = k
2x^2 + 1 = kx^2 - 2kx
(2 - k)x^2 + 2kx + 1 = 0
Real roots exist when the determinant ≥ 0.
(2k)^2 - 4(2 - k)(1) ≥ 0
4k^2 - 8 + 4k ≥ 0
k^2 + k - 2 ≥ 0
(k + 2)(k - 1) ≥ 0
k ≥ 1 or k ≤ 2