Чему равняется выражение?
B4–b1=52
b1•q^3–b1=52
b1(q^3–1)=52
b1(q–1)(q^2+q+1)=52 (1)
b1+b2+b3=26
b1+b1•q+b1•q^2=26
b1(1+q+q^2)=26 (2)
Разделим (1) на (2):
q–1=2
q=3
b1=52/(q^3–1)=52/26=2
b1•(q^6–1) 2•728
S6 = -------------- = --------- = 728
q–1 2
X(13-x)/(x+6)>0
x=0 x=13 x=-6
+ _ + _
----------------(-6)--------------(0)---------------(13)----------------
x∈(-∞;-6) U (0;13)
1)1/6x^2 = 2/12х² <span>
1/4х =</span> 3х/12х²<span>
</span><span>2)1/3х^2у= 12у</span>²/36х²у³<span>
1/12ху^2 = 2ху/36х</span>²у³<span>
1/18х^2у^3 = 2х</span>²/36х²у³<span>
3)1/(х+у)^2 = (х +у)/(х+у)</span>³<span>
1/(х+у)^3
4)1/(а-b)
1/(b-а) = -1/(а - b)
5)1/4х^2-1 и 1/1+2х
1/4х</span>² -1
(2х -1)/(4х² -1)