Вариант 20 ИДЗ 5.2

EDS - 5.2
№1.20 Prove that the function f (x) = sin7x + sinx; φ (x) = 4x as x → 0 are infinitesimal of the same order of smallness.
№2.20 Find the limits.
№3.20 Investigate these functions for continuity and build their graphs.
№4.20 Investigate these functions for continuity at the specified points. f (x) = ....; x1 = -2; x2 = -1.