One equation from the 1920s still describes how capital and labour make output

A mathematician and an economist fit US manufacturing data to a simple formula: output scales with capital and labour, each raised to its own power. Nearly a century later, the Cobb-Douglas function is still the default building block economists reach for to model growth and estimate how output splits between wages and profits.

— Charles W. Cobb and Paul H. Douglas, A Theory of Production — American Economic Review, 1928