шпора по физике за первый семестр / Биения

яю85=8O. 0AA<>B@8< @57C;LB0B A;>65=8O 2E >48=0:>2> =0?@02;5==KE :>;510=89, A >48=0:>2>9 0<?;8BC4>9, => A <0;>-@07;8G0NI8<8AO G0AB>B0<8: S1 = A cos wt ; S2 = A cos (w+ delta w)t, 345 delta w =0<=>3> <5=LH5 w; S = S1 + S2 = A [coswt + cos(w + delta w)t]

S = 2Acos(delta w t/2) * cos(wt + (delta w t / 2)).

"0: :0: delta w 7=0G8B5;L=> <5=LH5, G5< w, B> A><=>68B5;L cos(delta w t /2) 1C45B <5=OBLAO 7=0G8B5;L=> <54;5==55 2> 2@5<5=8, G5< coswt. "0:8< >1@07><, @57C;LB0B A;>65=8O 2E 1;87:8E ?> G0AB>B5 :>;510=89 <>6=> ?@54AB028BL :0: :>;510=8O B>9 65 G0AB>BK A <54;5==> <5=ONI59AO 0<?;8BC4>9, :>B>@0O @02=0 A0 = |2Acos (delta w t / 2)|. "0:85 :>;510=8O<8 A <54;5==> <5=ONI59AO 0<?;8BC4>9 =07K20NBAO 185=8O<8. (@8AC=>:  A8=CA>940 8 :>A8=CA>940, ?5@8>4, 2KA>B0 2A).