Ternary additive problems of Waring's type.
We prove in this article that almost all large integers have a representation as the sum of a cube, a biquadrate, ..., and a tenth power.
We study the sum τ of divisors of the quadratic form m₁² + m₂² + m₃². Let . We obtain the asymptotic formula S₃(X) = C₁X³logX + C₂X³ + O(X²log⁷X), where C₁,C₂ are two constants. This improves upon the error term obtained by Guo and Zhai (2012).