3.25. y = ctg 1/x · arccos x⁴.
(u·v)`=u`·v+u·v` u=ctg(1/x) u`=(–1/sin2(1/x))((1/x)`=(–1/sin2(1/x))·(–1/x2)=1/(x2·sin2(1/x)) v`=(arccosx4)`=–(x4)`/√1–(x4)2=–4x3/√1–(x4)2 О т в е т. (1/(x2·sin2(1/x))) · arccos(x4) + (ctg(1/x)) · (4x3/√1–x8)