- #1
silina01
- 12
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Prove that if x and y are not both , then x^4+x^3y+x^2y^2+xy^3+y^4 > 0
I have no idea how to start this proof, can anyone give me an idea?
I have no idea how to start this proof, can anyone give me an idea?
That'll do it. So how can you use that to rewrite the original expression?silina01 said:x^n - y^n = (x - y) (x^n-1 + x^n-2y+ ...+ xy^n-2 + y^n-1 )??
haruspex said:That'll do it. So how can you use that to rewrite the original expression?
Right, but there is one special case you need to address separately.silina01 said:ahhhh I see it know, in both cases if x-y <0 or if x-y>0 the quotient will always be positive. Thanks everyone.
Your expression involves 1/(x-y). What doubt should that create?silina01 said:what would that be?
silina01 said:x and y cannot be 0 by the way
Dick said:But they can be nonzero and equal.
dirk_mec1 said:But if you simplify the fraction then there is no problem.
A polynomial inequality is an expression in which two polynomials are compared using the symbols <, >, ≤, or ≥. It can be solved by finding the values of the variable that make the inequality true.
To prove a polynomial inequality, you must show that the inequality is true for all possible values of the variable. This can be done by using algebraic manipulation and properties of inequalities.
The steps to prove a polynomial inequality are:
Yes, you can use a graph to prove a polynomial inequality. Plotting the two polynomials on a graph allows you to visually see where the inequality holds true and where it does not. If the graph confirms the algebraic solution, then the inequality is proven.
Some common mistakes to avoid when proving a polynomial inequality are: