Question

B1=1 q=-2 S5=? геометрическая прогрессия

Answer 1

b4=1/2*(1/3)**3=1/54

s5=(1/2*((1/3)**5-1))/(1/3-1)=242/729

Answer 2

To find the value of S5 in a geometric progression with B1 = 1 and q = -2, we can use the formula for the sum of the first n terms of a geometric progression:

Sn = B1 * (1 - q^n) / (1 - q),

where Sn is the sum of the first n terms, B1 is the first term, q is the common ratio, and n is the number of terms.

In this case, B1 = 1 and q = -2. We need to find S5, which represents the sum of the first 5 terms. Plugging the values into the formula:

S5 = 1 * (1 - (-2)^5) / (1 - (-2)).

Simplifying further:

S5 = 1 * (1 - (-32)) / (1 + 2) = 1 * (1 + 32) / 3 = 33 / 3 = 11.

Therefore, the sum of the first 5 terms in the geometric progression with B1 = 1 and q = -2 is 11.