(√10 - 1)² - 3 (√10 + √3 - 1 )(√10 - √3 - 1 )
1/(2sqrt(x-1+x^(1/3))*(1+1/(3x^(2/3)
A₂=10 d=-2 S=-558 n-? >0
a₂=a₁+d=a₁+(-2)=10
a₁=12
S=(2*a₁+(n-1)*d)*n/2
(2*12+(n-1)*(-2))*n/2=-558 |×2
(24-2n+2)*n=1116
(26-2n)*n=1116
26n-2n²=1116 |÷(-2)
n²-13n-558=0 D=2401 √D=49
n₁=31 n₂=-18 ∉.
Ответ: n=31.
Q³=1*1/27=27
q=3
b1=b2/q=1/27/3=1/81
S6=1/81*(1-3^6)/1-3=...