Question

В геометрической прогрессии найдите b1, если q=3 и S5=484

Answer 1

q = 3     S₅ = 484     n = 5     b₁ = ?

$S_{5}=frac{b_{1}*(q^{5}-1)}{q-1}\\frac{b_{1}*(3^{5}-1)}{3-1} =484\\b_{1}*(243-1)=484*2\\b_{1} =frac{484*2}{242}=4\\b_{1} =4$