General Relativity: An Introduction for Physicists · Problem 2.9
Manifolds and coordinates — Hobson, Efstathiou & Lasenby
Physics · embedded-manifolds-volume-area
Problem
Show that the line element of a 3-sphere of radius a embedded in four-dimensional Euclidean space can be written in the form
ds2=a2[dχ2+sin2χ(dθ2+sin2θdϕ2)].
Hence, in this three-dimensional non-Euclidean space, calculate the area of the 2-sphere defined by χ=χ0. Also find the total volume of the three-dimensional space.