Question

Вычислите ctg(arccos(-4/5)+ arcctg(-1))

Answer 1

x=arccos(-4?5)<=>cos x=-4/5 π/2≤x≤ π=> ctg=-4/3.
y=arcctg(-1)<=>ctg y--1 & 0<y< π
ctg(x+y)=(ctg x-1)/(ctg x+ ctg y)={(-4/3)(-1)-1}/(-4/3-1)=(1/3)/(-7/3)=-1/7

Answer 2

а откуда там -4/3,

Answer 3

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