volume integral
Mathematical term for integrating a function over a three-dimensional region.
In this problem, you need to calculate the volume integral of the sphere.
線積分 is a line integral along a curve, whereas 体積分 integrates over a volume.
Compound of 体 (たい, 'body, volume') + 積分 (せきぶん, 'integral'). The term follows the pattern of other mathematical integrals such as 面積分 (surface integral) and 線積分 (line integral).