Find the set of values of k for which the curve y = kx^2 - 3x and the line y = x - k do not meet.
Solution
To find when the curve and the line do not meet, we set the equations equal to each other:
\(kx^2 - 3x = x - k\)
Rearrange to form a quadratic equation:
\(kx^2 - 4x + k = 0\)
For the curve and line not to meet, the discriminant of the quadratic must be less than zero:
\(b^2 - 4ac < 0\)
Here, \(a = k\), \(b = -4\), and \(c = k\). Calculate the discriminant:
\((-4)^2 - 4(k)(k) < 0\)
\(16 - 4k^2 < 0\)
Rearrange:
\(4k^2 > 16\)
\(k^2 > 4\)
Taking the square root of both sides gives:
\(k > 2 \text{ or } k < -2\)
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