In his work Nova stereometria doliorum vinariorum (New Solid Geometry of a Wine Barrel), published in 1615, astronomer Johannes Kepler stated and solved the following problem: Find the dimensions of the cylinder of largest volume that can be inscribed in a sphere of radius R. Hint: Show that an inscribed cylinder has volume 2πx(R2 − x2), where x is one-half the height of the cylinder.