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Find the values of k, so that the quadratic equation x2 – 4kx + k = 0 has equal roots |
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Answer» We know that quadratic equation ax2 + bx + c = 0 has equal roots if D = b2 – 4ac = 0. Therefore, given quadratic equation x2 – 4kx + k = 0 has equal roots if D = 0. ⇒(−4k)2 – 4 × 1 × k = 0. (∵ In equation x2 – 4kx + k = 0, a = 1, b = – 4k & c = k) ⇒ 16k2 – 4K = 0 ⇒ 4k (4k – 1) = 0 ⇒ k = 0 or 4k – 1 = 0 ⇒ k = 0 or k = \(\frac{1}{4}\) . Hence, for k = 1 and k = \(\frac{1}{4}\) , the quadric equation x2 – 4kx + x =0 has equal roots. |
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