Sin 60 = sqr(2)/2
tg 45 = 1
4*(0.5) - 2*1= 0
20016*820=16413120
30.543*650=19852950
18.209*340=6191060
458.200/790=580
936600/420=2230
166.680/360=463
835800/210=3980
Преобразуем ctg a = 1 / tg a.
(1/tg a)^2 - 1 1 - tg^2 a 1 - tg^2 a
------------------ = -------------- x tg a = -------------- .
1/tg a tg^2 a tg a
tg a 1 - tg^2 a
------------- x -------------- = 1.
<span>1 - tg^2 a tg a </span>