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f(x^3) - \sqrt3 /3 x^6 increases - All-Russian MO 2003 Regional (R4) 11.3

Source:

September 17, 2024
algebraIncreasing

Problem Statement

The functions f(x)xf(x)-x and f(x2)x6f(x^2)-x^6 are defined for all positive xx and increase. Prove that the function f(x3)32x6f(x^3) -\frac{\sqrt3}{2} x^6 also increases for all positive xx.