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# discrimminant for quartics AS maths watch

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2. (Original post by CasualSoul)
The quartic here is actually a quadratic in You could use a little substitution of to demonstrate this better if you wanted to
3. I wouldn't really call it a quartic. I mean, yes, it is x^4 but the x^3 is missing therefore if you let b=x^2 you've got a nice quadratic on which you can use the discriminant.
About the second part, I'm not really sure. I would end it at and say that this is true for any k therefore has real roots so and intersect for any k.
4. (Original post by kostis12345)
I wouldn't really call it a quartic. I mean, yes, it is x^4 but the x^3 is missing therefore if you let b=x^2 you've got a nice quadratic on which you can use the discriminant.
About the second part, I'm not really sure. I would end it at and say that this is true for any k therefore has real roots so and intersect for any k.
thanks- gave you rep :d

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