MathDB
Today's calculation of Integral 86

Source: 1984 Jyosai University Entrance exam

September 27, 2005
calculusintegrationtrigonometrycalculus computations

Problem Statement

Prove [πcosxx dx]2<1π2\left[\int_\pi^\infty \frac{\cos x}{x}\ dx\right]^2< \frac{1}{{\pi}^2}