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tehdiddulator
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Homework Statement
Let x [itex]\in[/itex] ℝ
Prove that if 3x[itex]^{4}[/itex]+1≤x[itex]^{7}[/itex]+x[itex]^{3}[/itex], then x > 0
Homework Equations
None
The Attempt at a Solution
Assume
3x[itex]^{4}[/itex]+1≤x[itex]^{7}[/itex]+x[itex]^{3}[/itex]
then 0 ≤ -3x[itex]^{4}[/itex]-1≤x[itex]^{7}[/itex]+x[itex]^{3}[/itex]
Then I assumed that each was greater than or equal to 0, which I thought gave the desired result. No examples in the book to really guide me...any help would be greatly appreciated.