A) 1/8
B) 8
C) 4
D) 1/4
Correct Answer: C
Solution :
Given parabola is \[{{y}^{2}}-kx+8=0\] \[\Rightarrow \] \[{{y}^{2}}=kx-8=k(x-8/k)=4AX\] where \[4\,A=k\] Directrix of the parabola is \[X+A=0\] Comparing it with \[x-1=0,\]we get \[1=\frac{8}{k}-\frac{k}{4}\] \[\Rightarrow \] \[4k=32-{{k}^{2}}\] \[\therefore \] \[k=-8,4\]You need to login to perform this action.
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