Question

sa se determine primi 2 termeni ai progresiei geometrice dn daca d8=256,q=4

Answer 1

$\displaystyle d_8=256,~q=4\\\\ d_n=d_1\cdot q^{n-1}\\\\ d_8=256 \Rightarrow d_1\cdot 4^{8-1}=256 \Rightarrow d_1 \cdot 4^7=256 \Rightarrow d_1 \cdot 4^7=4^4 \Rightarrow \\\\\Rightarrow d_1=\frac{4^4}{4^7} \Rightarrow d_1=\frac{1}{4^3}\Rightarrow d_1= \frac{1}{64}$

$\displaystyle d_2=\frac{1}{64} \cdot 4^{2-1}\Rightarrow d_2=\frac{1}{64} \cdot 4^1\Rightarrow d_2=\frac{4}{64} \Rightarrow d_2=\frac{1}{16}$