Вопрос школьника по предмету Алгебра
Найдите а1,d,а26 для арифметической прогрессии (аn): 10;4;-2
Найдите b1 и q для геометрической прогрессии(bn)у которой b2=4 b3=2
Найдите пятый член геометрический прогрессии (bn)если b1=1/3 q=3
Является ли число А=64 членом геометрической прогрессии 0.5;1;…?Если да,то укажите его номер
Ответ учителя по предмету Алгебра
1) a1=10; 2) d=-2-4=-6; 3) a26=10-25*6=10-150=-140
2) b1g =4; b1g^2=2. Разделим первое равенство на второе получим 1/g=2, отсюда g=1/2. b1=4*2=8
3) b5= 1/3*3^4=27.
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