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Find the values of k for which the following equations have real and equal roots:
$k^2x^2 - 2(2k - 1)x + 4 = 0$
Given:
Given quadratic equation is $k^2x^2 – 2(2k - 1)x + 4 = 0$.
To do:
We have to find the values of k for which the roots are real and equal.
Solution:
Comparing the given quadratic equation with the standard form of the quadratic equation $ax^2+bx+c=0$, we get,
$a=k^2, b=-2(2k-1)$ and $c=4$.
The discriminant of the standard form of the quadratic equation $ax^2+bx+c=0$ is $D=b^2-4ac$.
$D=[-2(2k-1)]^2-4(k^2)(4)$
$D=4(2k-1)^2-(16)(k^2)$
$D=4(4k^2-4k+1)-16k^2$
$D=16k^2-16k+4-16k^2$
$D=-16k+4$
The given quadratic equation has real and equal roots if $D=0$.
Therefore,
$-16k+4=0$
$16k=4$
$k=\frac{4}{16}$
$k=\frac{1}{4}$
The value of $k$ is $\frac{1}{4}$.
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