#971 · Algebra · Inequalities

Inequality for four continued proportionals

If four positive numbers $a, b, c, d$ are in continued proportion (so $\frac{a}{b} = \frac{b}{c} = \frac{c}{d}$ ), show that $a - d \geq 3 (b - c)$ .

~8 minProof · checked by AIproportioninequality

H. S. Hall & S. R. Knight, Higher Algebra (1891) · Ch. II. Proportion, Examples II, No. 22

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