Show $1-1/x <\ln(x)
for all x>1?
My attempt:
(1) $\ln (x)
Suppose h:R+→R,t↦t−1−ln(t), then h′(t)=0 if t=1. Furthermore h′(t)>0 for all t∈R+.
(2) 1−1/x<ln(x)
Suppose f:R+→R,t↦ln(t)−1+1t, then f′(t)=0 for t=1 and f′(t)>0 for all t∈R+.
Therefore the inequality is true.
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