Сумма первых двух членов геометрической прогрессии равна 4, а сумма первых трех ...

August 2022 1 1 Report

Сумма первых двух членов геометрической прогрессии равна 4, а сумма первых трех членов равна 13. Найдите сумму пяти первых членов

Answers & Comments

Pacanka202 B1+b2=4
b1+b2+b3=13
b3=13–4=9
(b2)^2=b1•b3=9b1
Пусть b1=x
(4–x)^2=9x
16–8x+x^2–9x=0
x^2–17x+16=0
x1+x2=17
x1•x2=16
x1=1; x2=16
b1=1; b2=3; q=3
S5 =(b1•(q^5 – 1))/(q–1)=(1•242)/2=121

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Answers & Comments

dany razlozheniya chisel na prostye mnozhitelinajdite ih nokc2335 i d225

azastan baj lke pomogite napisat sochinenie

5 kg massa skolkih litrov kerosina ravna 1 kgb59682d87f275d05ac243405df57677e 91464

summa vseh reber kuba ravna 69 sm najdite dlinu rebra kuba8b4283ff4af724f2afa4aa0abfb3db0f 92082

5 m skolko shagov sdelaet rebenok projdya rasstoyanie ravnoe 100 m192898313ba1a63e998ddb31f17a939e 18892

2414e64397463cf5b80b5fd37107336fa3 34908

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