Вариант 28 ИДЗ 5.2

EDS - 5.2
# 1.28 Prove that the functions f (x) = 1 - cos 4x; φ (x) = x · sin 2x as x → 0 are infinitesimal of the same order of smallness.
№2.28 Find the limits.
№ 3.28 Investigate these functions for continuity and build their graphs.
№4.28 Investigate these functions for continuity at the specified points. f (x) = 4x / (x + 5); x1 = -5; x2 = -4;