Original post by nonipaify
...
It should be. Maybe it was specified that or perhaps that is positive?
By the way, that's a quadratic polynomial, not a cubic, as the highest order of x when expanded is 2. Hence why there are also 2 solutions for x.
As the person above me stated, maybe you missed something in the question that directed you to one of the answers? Was the equation describing something physical like the height of a wall? If so, a negative answer wouldn't make sense.
Posted from TSR Mobile
As the person above me stated, maybe you missed something in the question that directed you to one of the answers? Was the equation describing something physical like the height of a wall? If so, a negative answer wouldn't make sense.
Posted from TSR Mobile
Original post by Curtailment
By the way, that's a quadratic polynomial, not a cubic, as the highest order of x when expanded is 2. Hence why there are also 2 solutions for x.
No it's cubic. The highest power when you expand is 3.
Original post by notnek
No it's cubic. The highest power when you expand is 3.
Ah, my bad. On my phone and didn't notice that the first bracket is squared.
OK so there will be three solutions, a positive/negative pair and another value.
Original post by Curtailment
Ah, my bad. On my phone and didn't notice that the first bracket is squared.
OK so there will be three solutions, a positive/negative pair and another value.
OK so there will be three solutions, a positive/negative pair and another value.
The polynomial posted only has two solutions. It is not true that cubics have 'positive/negative' pairs as solutions, at least generally, and at least if I understood what you meant. y = (x-1)^3 is a polynomial with one positive solution, and no negative solutions.
Original post by Forum User
The polynomial posted only has two solutions. It is not true that cubics have 'positive/negative' pairs as solutions, at least generally, and at least if I understood what you meant. y = (x-1)^3 is a polynomial with one positive solution, and no negative solutions.
I think he meant 'positive/negative' pairs of solution for the quadratic factor,
but this is not the case when e.g x^2 =4 -> x1,2 = +-2, but the complete
quadratic is equal with 0 so we have one solution, exactly a solution repeated twice.
So y=(x-1)^3 is a polynimoal with 3 solutions, a positive aolution repeated 3 times.
A cubic polynomial (with real coeffitients and constant) always has 3 roots,
where at least 1 root is real (the other two maybe complex conjugate but even all real)
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