Вариант 26 ИДЗ 5.2

EDS - 5.2
# 1.26 Prove that the functions f (x) = cos x - cos3 x; φ (x) = 6x2 as x → 0 are infinitesimal of the same order of smallness.
№2.26 Find the limits.
№ 3.26 Investigate these functions for continuity and build their graphs.
No. 4.26 Investigate these functions for continuity at the specified points. f (x) = (x + 5) / (x-3); x1 = 3; x2 = 4;