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# How does the discriminant relate to this?

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1. I did part a), but I fail to understand the rest of it. Could someone clear this out for me? I know that 'equal roots' implies that the discriminant is involved in solving the problem and b^2 - 4ac = 0. The curve will touch the x-axis, but how does that help me in finding k?
2. (Original post by frostyy)
I did part a), but I fail to understand the rest of it. Could someone clear this out for me? I know that 'equal roots' implies that the discriminant is involved in solving the problem and b^2 - 4ac = 0. The curve will touch the x-axis, but how does that help me in finding k?
The discriminant is .
3. I understand that, but I'd like to know the logic behind that helping me to find k.
And how would I solve it? Set 64k^2 - 4k = 0 and then just simply get k?

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4. (Original post by frostyy)
I understand that, but I'd like to know the logic behind that helping me to find k.
And how would I solve it? Set 64k^2 - 4k = 0 and then just simply get k?

Posted from TSR Mobile
It gets you an equation in , which you can then solve for .

Yep, and you know that .
5. The fact that the discriminant = 0 means that the line is a tangent to the curve at the point of intersection.
I want to clarify that because the discriminant = 0 that does not mean that the original curve will touch the x axis as you incorreclty said in your post.
6. But, at the same time, it does mean that the curve does touch the x-axis.

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