2/(х-3) - 18х/(х³-27) - (х-3)/(х²+3х+9) =
= 2/(х-3) - 18х/(х-3)(х²+3х+9) - (х-3)/(х²+3х+9) =
= 2(х²+3х+9)/(х-3)(х²+3х+9) - 18х/(х-3)(х²+3х+9) - (х-3)(х-3)/(х-3)(х²+3х+9) =
= (2х²+6х+18)/(х-3)(х²+3х+9) - 18х/(х-3)(х²+3х+9) - (х²-6х+9)/(х-3)(х²+3х+9) =
= (2х²+6х+18 - 18х - х²+6х-9)/(х-3)(х²+3х+9) =
= (х²-6х+9)/(х-3)(х²+3х+9) =
= (х-3)² / (х-3)(х²+3х+9) =
= (х-3) / (х²+3х+9),
а)
при x = 0: (0-3) / (0²+3*0+9) = -3/9 = -1/3,
б)
при x = 3: (3-3) / (3²+3*3+9) = 0/27 = 0
Ответ:
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6. s=gt^2/2
s=560. g=10. 2s=gt^2. t^2=2s/g. t=корень из 2s/2 = корень из 112= 23.7с Ответ: t=23.7 с высоты 560 м.