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Question

Find k such that \(x^2 -2(k+1)x + (k^2+1)=0\) has distinct real roots.

This question was previously asked in
UPTET 2026 Paper 2 Social Studies Question Paper (3-Jul-2026) (Shift 1)
The correct answer is

k>0

For distinct real roots, the discriminant must be strictly positive: \(b^2-4ac>0\).

Here \(a=1,\ b=-2(k+1),\ c=(k^2+1)\), so \(4(k+1)^2 - 4(k^2+1) > 0\).

Dividing by 4: \((k+1)^2 - (k^2+1) > 0 \Rightarrow k^2+2k+1-k^2-1>0 \Rightarrow 2k>0\).

This simplifies to \(k>0\).

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Important Questions from Quadratic Equations

  1. If k = c, then the roots of the equation are:

  2. If \(\rm {k}=\frac{{c}}{2},({c} \neq 0)\), then the roots of the equation are :

  3. What is the number of real roots of the equation?

  4. What is the sum of all the roots of the equation?

  5. If α and β are the distinct roots of equation x2 - x + 1 = 0, then what is the value of \(\left|\frac{\alpha^{100}+\beta^{100}}{\alpha^{100}-\beta^{100}}\right|\) ?

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