If the line x – 1 = 0 is the directrix of the parabola y2 – kx + 8

1.	If the line x – 1 = 0 is the directrix of the parabola y2 – kx + 8 = 0, then one of the value of k
Answer» The parabola is y² - kx + 8 = 0 y² = kx - 8 = k(x - 8/k) = 4AX where 4A = K direction of the parabola is X + A = 0 Comparing it with x - 1 = 0 we get 1 = 8/k - K/4 or k² + 4k - 32 = 0 (k + 8)(k - 4) = 0 k + 8 = 0 or k - 4 = 0 k = -8 or k = 4 Hence, the value of k is 4.

If the line x – 1 = 0 is the directrix of the parabola y2 – kx + 8 = 0, then one of the value of k

Answer»

The parabola is y² - kx + 8 = 0

y² = kx - 8

= k(x - 8/k)

= 4AX

where 4A = K

direction of the parabola is X + A = 0

Comparing it with x - 1 = 0 we get

1 = 8/k - K/4

or k² + 4k - 32 = 0

(k + 8)(k - 4) = 0

k + 8 = 0 or k - 4 = 0

k = -8 or k = 4

Hence, the value of k is 4.

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If the line x – 1 = 0 is the directrix of the parabola y2 – kx + 8 = 0, then one of the value of k

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